Jet singulation

ABSTRACT

Techniques for singulating a substrate into a plurality of component parts is disclosed. The singulation techniques include generating a jet stream in order to cut through large components so as to produce smaller components. The techniques are particularly suitable for singulating surface mount devices such as chip scale packages, ball grid arrays (BGA), flip chips, lead less packages (QFN) and the like. The techniques are also suitable for singulating photonic devices.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the priority of the following U.S. PatentApplications, which are hereby incorporated herein by reference:

U.S. patent application Ser. No. 10/661,385 filed on Sep. 12, 2003 andentitled JET SINGULATION, which claims priority to U.S. ProvisionalApplication No. 60/410,744 entitled “JET SINGULATION”, filed on Sep. 13,2002 and U.S. Provisional Application No. 60/562,788 entitled “JETSINGULATION”, filed on Apr. 15, 2004 which are all incorporated hereinby reference.

FIELD OF THE INVENTION

The invention generally relates to integrated circuit processingequipment. More particularly, the invention relates to an improvedapparatus and method of singulating a substrate into a plurality ofcomponent parts.

BACKGROUND OF THE INVENTION

A singulation procedure is typically performed to separate integratedcircuit packages such as IC chips from a substrate such as a circuitboard. During singulation, the substrate is typically held in placewhile one or more saw blades cut straight lines through the substrate toform the individual integrated circuit packages. Although dicing withsaw blades has worked well, continuing advancements in the industry havetested the limitations of saw singulation.

Cutting small devices is particularly problematic for saw singulation.When device dimensions are small as for example less than 3 mm×3 mm,vacuum fixtures are unable to retain the small devices during sawing,with consistency. As the saw blade passes through a device, it is bothrotating and translating relative to the device under process. Theresulting force vectors have both vertical and shear components. As theshear component overwhelms the holding force of the vacuum fixture, thesingulation yield drops due to non-conforming geometries, damage, orlost parts. As feed rates increase, the magnitude of the shear componentincreases commensurately and magnifies the device retention problem.Therefore, feed rates are minimized to protect yields. The result,however, is lower throughput.

High consumable cost is also problematic for saw singulation. Sawsingulation may require specially formulated blades that must constantlyexpose new diamonds to the cut interface. As the diamonds removematerial, they are “dulled” by the materials used in the substrate andmust be sloughed-off as the blade wears at a higher-than-normal rate.The balance between blade wear and cut quality is a delicate trade-offrequiring costly technology to extend blade life while minimizing burrsand chips.

Curvilinear cutting paths are also problematic for saw singulation. Manynew devices as for example photonic devices are produced with precisecurved boundaries rather than straight edges. Curved boundaries requirecurvilinear cut paths, which saw blades do not readily accommodate. Bydefinition, the cut path of a rotating blade must be the straight linedefined by the intersection of the blade plane and the device plane. Sawsingulation simply does not lend itself to curvilinear cutting paths asneeded by these new devices.

Based on the foregoing, there is desired an improved apparatus andmethod of singulating a substrate into a plurality of component parts.

SUMMARY OF THE INVENTION

The invention relates, in one embodiment, to a singulation engine forperforming cutting operations on semiconductor substrates. Thesingulation engine includes a slurry vessel for mixing an abrasiveslurry before the abrasive slurry is delivered to a nozzle system. Thesingulation engine also includes an abrasive source configured tointroduce new abrasive into the slurry vessel. The singulation enginefurther includes a fluid source configured to introduce new fluid intothe slurry vessel. The singulation engine additionally includes arecycled slurry source configured to reintroduce previously usedabrasive slurry back into the slurry vessel. Moreover, the singulationengine includes one or more concentration sensing devices configured toperform measurements so that the abrasive slurry concentration can beascertained, and a controller configured to control the amount ofabrasive, fluid and recycled abrasive slurry introduced into the slurryvessel based on the concentration measurements.

The invention relates, in another embodiment, to an opticalconcentration sensor for measuring a moving abrasive slurry associatedwith a singulation engine capable of cutting semiconductor substrates.The optical concentration sensor includes a housing that defines aslurry passage therein. The slurry passage is configured to distribute amoving slurry between an inlet coupling and an outlet coupling. Thehousing includes one or more windows that provide optical access to theslurry passage. The windows are formed from a light passing materialthat substantially withstands a moving abrasive slurry and does notcontribute to contamination of the moving abrasive slurry. The opticalconcentration sensor also includes a light source configured to directlight into the slurry passage through the window. The light isconfigured to intersect an abrasive slurring moving through the slurrypassage. The optical concentration sensor further includes one or morelight detectors configured to detect light traveling out of the slurrypassage through one or more windows. The light detectors produce signalsin accordance with the light intensity of the light traveling out of theslurry passage through the one or more windows. The light intensityvaries in accordance with the concentration of the moving abrasiveslurry.

The invention relates, in another embodiment, to a slurry controlmethod. The method includes performing measurements on a moving slurry.The method also includes translating measurements into measuredconcentration. The method further includes comparing measuredconcentration with a desired concentration. The method additionallyincludes controlling an input to the moving slurry based on thecomparison.

The invention relates, in another embodiment, to an abrasive source. Theabrasive source includes a removable abrasive canister that is preloadedwith an abrasive material. The preloaded removable canister isconfigured for manipulation by an operator. The abrasive source alsoincludes an abrasive delivery receptacle that resides within an abrasivedelivery system and that operatively couples the removable abrasivecanister to the abrasive delivery system.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by reference to the followingdescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a simplified block diagram of a cutting apparatus inaccordance with one embodiment of the present invention.

FIG. 2A is a simplified perspective diagram of a fine beam cuttingthrough a substrate to form individual packaged devices, in accordancewith one embodiment of the present invention.

FIG. 2B is a simplified perspective diagram of a fine beam cuttingthrough a substrate to form photonic devices, in accordance with oneembodiment of the present invention.

FIG. 3A is a bottom view of a substrate having a plurality of lead lessintegrated circuit packages formed thereon.

FIG. 3B is a top view of a substrate having a plurality of lead lessintegrated circuit packages formed thereon.

FIG. 3C is a top view of a group of singulated lead less integratedcircuit packages.

FIG. 3D is a side view of a singulated integrated circuit package.

FIG. 3E is a perspective view of a singulated integrated circuitpackage.

FIG. 4A is a top view of a substrate having a plurality of ball gridarray (BGA) integrated circuit packages formed thereon.

FIG. 4B is a top view of a group of singulated BGA integrated circuitpackages.

FIG. 4C is a side view of a singulated BGA integrated circuit package.

FIG. 4D is a perspective view of a singulated BGA integrated circuitpackage.

FIG. 5 is an illustration showing a photonic devices after singulation.

FIG. 6 is a simplified diagram of a singulation engine, in accordancewith one embodiment of the present invention.

FIG. 7A is a front view, in cross section, of a gang manifold assembly,in accordance with one embodiment of the present invention.

FIG. 7B is a side view, in cross section, of a gang manifold assembly,in accordance with one embodiment of the present invention.

FIG. 8 is a side view, in cross section, of a nozzle, in accordance withone embodiment of the present invention.

FIG. 9 is a side view, in cross section, of an abrasive slurry deliveryassembly, in accordance with one embodiment of the present invention.

FIG. 10 is a simplified side view of a wet slurry filter arrangement, inaccordance with one embodiment of the present invention.

FIG. 11 is a top view of a chuck assembly, in accordance with oneembodiment of the present invention.

FIG. 12A is a top view of a chuck assembly, in accordance with analternate embodiment of the present invention.

FIG. 12B is a top view of a chuck assembly, in accordance with analternate embodiment of the present invention.

FIG. 12C is a top view of a chuck assembly, in accordance with analternate embodiment of the present invention.

FIG. 13 is a perspective view of a chuck assembly, in accordance withone embodiment of the present invention.

FIG. 14 is an exploded view of the chuck assembly shown in FIG. 13, inaccordance with one embodiment of the present invention.

FIG. 15 is a simplified side view, in cross section, of a chuck, inaccordance with one embodiment of the present invention.

FIG. 16 is a simplified side view, in cross section, of a chuck, inaccordance with one embodiment of the present invention.

FIGS. 17A–F are diagrams of a vacuum platform, in accordance with oneembodiment of the present invention.

FIGS. 18A–E are diagrams of a vacuum platform, in accordance with oneembodiment of the present invention.

FIGS. 19A–E are diagrams of a rubber like vacuum platform, in accordancewith one embodiment of the present invention.

FIGS. 20A–F are diagrams of a vacuum manifold, in accordance with oneembodiment of the present invention.

FIGS. 21A–G are diagrams of a vacuum manifold, in accordance with oneembodiment of the present invention.

FIGS. 22A–J illustrate a cutting sequence using the gang manifoldassembly shown in FIGS. 7A and 7B and the chuck assembly shown in FIGS.13 and 14, in accordance with one embodiment of the present invention.

FIGS. 23A and 23B are top view diagrams showing serpentine paths, inaccordance with one embodiment of the present invention.

FIG. 24 is a flow diagram of a cutting method, in accordance with oneembodiment of the present invention.

FIG. 25 is a simplified diagram of a singulation engine, in accordancewith one embodiment of the present invention.

FIG. 26 is a diagram showing a gang manifold initiation sequence, inaccordance with one embodiment.

FIG. 27 is a block diagram of a singulation engine, in accordance withone embodiment of the present invention.

FIG. 28 is a diagram of a concentration sensing device, in accordancewith one embodiment of the present invention.

FIG. 29 is a side elevation view, in cross section, of an opticalconcentration sensor, in accordance with one embodiment of the presentinvention.

FIG. 30 is a front elevation view, in cross section, of an opticalconcentration sensor, in accordance with one embodiment of the presentinvention.

FIG. 31 is a slurry control method, in accordance with one embodiment ofthe present invention.

FIG. 32 is a concentration determination method, in accordance with oneembodiment of the present invention.

FIG. 33 is a simplified illustration of an abrasive distributionsequence, in accordance with one embodiment of the present invention.

FIG. 34 is diagram of an abrasive source, in accordance with oneembodiment of the present invention.

FIG. 35 is an exploded perspective view of an abrasive canister, inaccordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally relates to an improved apparatus andmethod for singulating a substrate into a plurality of component parts.More particularly, the invention relates to a singulation system capableof singulating integrated circuit devices (e.g., dies, unpackaged chips,packaged chips, and the like). The singulation system is configured togenerate a jet stream that contains an abrasive and fluid that cutsthrough large components so as to produce smaller components. The systemdescribed herein is particularly suitable for singulating surface mountdevices such as chip scale packages, ball grid arrays (BGA), flip chips,lead less packages (QFN) and the like. The system is also suitable forsingulating photonic devices.

Water jet machining has been available for decades; however, itspotential has never been realized in semiconductor manufacturing. Thefine geometries required by semiconductor manufacturers were beyond thereach of traditional water jets and their nozzle technologies. Thoughsmall aperture nozzles delivered sufficiently fine beams of water, thenozzle aperture would increase with use causing unacceptable deviationsfrom target geometries. In addition, traditional water jets rely on theimpact forces of high-energy water means to erode material.Manufacturers with expensive clean rooms have been concerned about thesehigh pressures, since a relatively small leak at 40,000 psi can bedevastating. Some water jets operate at lower pressures by employing anabrasive mixed with the water; however these can only provide cut widthsdown to 0.5 mm. The cut beams of abrasive water jets have traditionallybeen difficult to control. As dry abrasive is introduced into thepressurized water stream, a large amount of air is also introduced. Thisair destroys any hope of generating a consistent and dense coherent beamof water. The resulting spreading beam cannot produce the small cutwidths or the 25 micron tolerance required in semiconductor singulation.The present invention overcomes these disadvantages.

Embodiments of the invention are discussed below with reference to FIGS.1–35. However, those skilled in the art will readily appreciate that thedetailed description given herein with respect to these figures is forexplanatory purposes as the invention extends beyond these limitedembodiments.

FIG. 1 is a simplified block diagram of a cutting apparatus 10, inaccordance with one embodiment of the present invention. The cuttingapparatus 10 is configured to produce a cutting beam 11 capable ofcutting through a substrate 12 in order to form small discrete parts.For example, the cutting beam may be configured to singulate a substrateinto a plurality of individual packaged devices including but notlimited to CSPs, BGAs, QFNs and the like. The cutting beam may also beconfigured to singulate a substrate into photonic devices such asarrayed wave grating photonic devices.

The cutting apparatus 10 generally includes an abrasive delivery system14 and a nozzle 16 operatively coupled to the abrasive delivery system14. The abrasive delivery system 14 is configured to supply an abrasiveslurry to the nozzle 16 and the nozzle 16 is configured to produce acutting beam 11 with the abrasive slurry. The abrasive slurry istypically formed by an abrasive and a fluid. The cutting nature of thebeam 11 relies on the fluid to carry the abrasive and on the abrasive toremove the material from the substrate 12. In most cases, the abrasiveslurry is squeezed through a small opening in the nozzle 16. Squeezingthe slurry through the nozzle 16 causes it to exit the nozzle 16 in avery fine and high speed cutting beam 11.

As shown in FIG. 1, the abrasive delivery system 14 generally includes apump 18, a slurry vessel 20 and a slurry source 22. The pump 18 isconfigured to pump the abrasive slurry out of the slurry vessel 20 anddeliver the abrasive slurry to the nozzle 16. The slurry vessel 20 isconfigured to contain the abrasive slurry and may serve as a locationfor mixing the components (e.g., abrasive and fluid) of the abrasiveslurry. The slurry source 22, on the other hand, is configured to supplythe components of the abrasive slurry. For example, the slurry sourcemay distribute the abrasive, fluid, or other component of the slurryseparately and/or mixed. The slurry source may for example includestorage containers that contain the individual or mixed components ofthe abrasive slurry. The components may be pumped into the slurry vesselusing any suitable technique.

In one embodiment, the abrasive delivery system 14 is a re-circulatorysystem. For example, the abrasive slurry is recaptured after cuttingthrough the substrate 12 and recycled for future use. In cases such asthese, a filter may be used to prevent cut particles from entering thedelivery system, i.e., the cut particles may be larger than theabrasives and thus they have the ability to clog the system. In anotherembodiment, the abrasive delivery system 14 is not a recirculatorysystem. In this embodiment, new components are continuously supplied andused components are discarded, i.e., the slurry is continuouslyrefreshed. As should be appreciated, this type of system preventsparticle contamination altogether. In one implementation, the abrasiveis pumped into the slurry vessel at low pressure before the fluid ispumped into the slurry vessel at high pressure. In order to transfer theabrasive to the slurry vessel the typically dry abrasive may bedelivered to the slurry vessel in a wet condition. In some cases, theaforementioned embodiments may be combined to both re-circulate usedmaterial and add new material to the system.

The diameter of the cutting beam 11 is small in order to dice smallparts such as packaged or photonic devices. The cutting beam 11typically produces cut widths in the substrate with similar dimensionsas the diameter of the cutting beam. The diameter of the cutting beam isgenerally determined by the diameter of the opening in the nozzle. Thediameter of the cutting beam generally corresponds to the diameter ofthe opening in the nozzle. Although not a requirement, the diameter ofthe beam is typically on the order of about 0.050 mm to about 3.0 mm,and more particularly between about 0.25 mm and about 0.3 mm. This rangeis well within the typically saw street dimensions for packaged andphotonic devices.

As shown in FIGS. 2A and 2B, the cutting beam 11 may be used to makerectilinear cuts (FIG. 2A) as for example when forming individualpackaged devices and/or curvilinear cuts (FIG. 2B) as for example whenforming wave grating photonic devices. These types of cuts may beaccomplished by moving the substrate 12 and/or the cutting beam 11relative to one another. For example, the substrate 12 may be moved by astage and/or the nozzle 16 may be moved by a robot. In FIG. 2A, the zaxis oriented beam 11 is moved in the x direction to make parallel rowsof x directed rectilinear cuts 28, and in the y direction to makeparallel rows of y directed rectilinear cuts 30. Rectilinear cuts suchas x and y directed cuts are suitable for singulating individualpackaged devices 24 such as CSPs, BGAs, QFNs and the like. One advantageof cutting package devices with this type of cutting method is that thecutting beam interacts with the substrate along the z axis therebypreventing the formation of shear forces that can adversely effect thesingulated packages. In FIG. 2B, the z axis oriented beam 11 is moved inboth the x and y directions (simultaneously or incrementally) in orderto make curvilinear cuts.

FIGS. 3A–3E are illustrations showing lead less integrated circuitpackages before and after being singulated from a substrate with acutting beam, in accordance with one embodiment of the presentinvention. By way of example, the cutting beam may generally correspondto the cutting beam discussed in the previous Figures. FIGS. 3A and 3Bshow a substrate 32 before singulation. As shown, the substrate 32 isformed by a plurality of integrated circuit packages 33. Although not arequirement, the packages 33 are generally formed in rows and columns onthe substrate 32. Furthermore, the integrated circuit packages 33 may bepositioned in one or more closely packed groups 34. FIG. 3C shows agroup 34 of leadless integrated circuit packages 33 after being cut fromthe substrate 32. The group 34 may correspond to any of the four groups34 shown in FIGS. 3A and 3B. FIGS. 3D and 3E show a single integratedcircuit package 35 after being separated from the group 34. Lead lesspackages are generally well known in the art and for the sake of brevitywill not be discussed in any greater detail.

In one particular embodiment, the substrate 32 corresponds to thosesubstrates that contain Quad Flat Pack No Lead (QFN) packages. QFNpackages generally refer to leadless packages with peripheral terminalpads and an exposed die pad. QFN packages may be used in a variety ofapplications including cell phones, personal digital assistants,portable music players, portable video players and the like. QFNsubstrates typically include a copper carrier A, and a mold compound Bthrough which the cutting beam cuts in order to singulate the individualQFN packages 33 from the substrate 32. It should be noted that QFNpackages are not a limitation and that other types of packages may beused.

FIGS. 4A–4D are illustrations showing a plurality of ball grid array(BGA) integrated circuit packages before and after being singulated froma substrate with a cutting beam, in accordance with one embodiment ofthe present invention. By way of example, the cutting beam may generallycorrespond to the cutting beam discussed in the previous Figures. BGAintegrated circuit packages typically refer to a packaging technologythat allows an integrated circuit to be attached to a printed circuitboard face-down, with the chip's contacts connecting to the printedcircuit board's contacts through individual balls of solder. Duringfabrication thereof, multiple integrated circuit chips (ball grid arraysand dies) are formed on a single substrate (e.g., wafer or circuitboard), and thereafter separated into a plurality of individual orsingle integrated circuit chips. Although a substrate may be separatedat substantially any point during an overall fabrication process, thesubstrate is typically separated after the ball grid arrays and dies areformed on the substrate.

To elaborate, FIG. 4A shows a substrate 36 formed by a plurality of BGAintegrated circuit packages 37 before singulation. FIG. 4B shows a group38 of BGA integrated circuit packages 37 after singulation. FIGS. 4C and4D show a single BGA integrated circuit package 37 after being separatedfrom the group 38. BGA integrated circuit packages are generally wellknown in the art and for the sake of brevity will not be discussed inany greater detail.

FIG. 5 is an illustration showing a photonic device 39 aftersingulation, in accordance with one embodiment of the present invention.

FIG. 6 is a simplified diagram of a singulation engine 40, in accordancewith one embodiment of the present invention. The singulation engine 40is configured to singulate a substrate 42 into smaller component partsvia a cutting beam 44. By way of example, the component parts may beCSPs, BGAs, QFNs, photonic devices and the like. The singulation engine40 includes a jet stream distribution unit 46 formed by at least anozzle assembly 47, an abrasive slurry delivery assembly 48 and a tankassembly 49. The abrasive slurry delivery assembly 48 is configured todeliver an abrasive slurry to the nozzle assembly 47. The nozzleassembly 47 is configured to discharge a jet stream in a laminar andcollimated manner towards the substrate 42 in order to produce thecutting action of the cutting beam 44. The tank assembly 49 isconfigured to receive and diffuse the jet stream once it passes throughthe substrate 42 during the cutting action.

During operation, for example, the abrasive slurry delivery assembly 48supplies the nozzle assembly 47 with the abrasive slurry and the nozzleassembly 47 directs the abrasive slurry towards the substrate 42. Oncedischarged from the nozzle assembly 47, the abrasives in the slurry workagainst the substrate 42 to remove material therefrom. Almostinstantaneously, the cutting beam 44 forms a hole through the substrate42. After forming the hole, the cutting beam 44 continues along its pathuntil it reaches a medium stored in the tank assembly 49.

The nozzle assembly 47, abrasive slurry delivery assembly 48 and tankassembly 49 may be widely varied. In the illustrated embodiment, thenozzle assembly 47 includes one or more nozzles 50 coupled to a nozzlemanifold 52. The one or more nozzles 50 are configured to direct theabrasive slurry towards the substrate 42 in the form of one or morecutting beams 44. Each of the nozzles 50 includes an opening 51 throughwhich the abrasive slurry is discharged. The size of the opening 51generally effects the size of the cutting beam 44, which in turn effectsthe width of the cut in the substrate 42. The nozzle manifold 52 isconfigured to distribute the abrasive slurry from the abrasive deliverysystem 48 to the one or more nozzles 50. As shown, the nozzle manifold52 is coupled to the abrasive slurry delivery system 48 via one or moretubes 54A. The number of nozzles and thus the number of cutting beamsmay vary according to the specific needs of each device.

The abrasive delivery assembly 48, on the other hand, includes a highpressure pump 55, an abrasive slurry vessel 56, and an abrasive slurrysource 57. The high pressure pump 55 is configured to pump fluid to theabrasive slurry vessel 56 in order to carry and deliver the abrasiveslurry to the nozzle assembly 47 at very high pressures. By way ofexample, the high pressure pump may pressurize the slurry vessel withpressures ranging between about 1,000 PSI to about 50,000 PSI. Theslurry vessel 56 is configured to contain the abrasive slurry beforebeing sent to the nozzle assembly 47 and may serve as a location formixing the components (e.g., abrasive and fluid) of the abrasive slurry.The slurry source 57 is configured to supply the components of theabrasive slurry. The abrasive is generally introduced into the slurryvessel 56 at low pressures as for example between about 10 and about 75PSI. The slurry source 57 may be a re-circulatory and/or non circulatorysystem. That is, the slurry source 57 may supply previous used abrasiveslurry and/or it may supply new components to the abrasive slurryvessel.

It has been found that the slurry should be completely devoid of air inorder to maintain small diameter cutting beams as for example 50 microncutting beams. In one implementation, the abrasive is first soaked withwater at ambient pressure as it is introduced into the singulationsystem. The wet abrasive is then introduced into the slurry vessel 56and exposed to high-pressure water via the high pressure pump. Once theabrasive/water mixture is pressurized, the abrasive slurry moves throughhigh-pressure tubing 54A to the nozzle assembly 47.

Referring to the tank assembly 49, the tank assembly 49 typicallyincludes a holding tank 58, which contains a medium 60 for diffusing thejet stream. The medium may for example correspond to a slurry such asthe abrasive slurry used to cut the substrate. In some cases, theabrasive slurry is mixed and held in the holding tank 58 before beingsent to the abrasive slurry vessel 56. For example, the holding tank 58may serve as the abrasive slurry source for the abrasive deliveryassembly 48. In cases such as these, the holding tank 58 may include oneor more inlets/outlets for refilling and removing the components of theabrasive slurry. Furthermore, the holding tank 58 may be coupled to theabrasive slurry delivery assembly 48 and more particularly the slurryvessel via one more tubes 54B. In order to prevent contaminants (causedby the cutting action) from entering the abrasive slurry deliveryassembly 48, a filter mechanism 61 may be placed between the holdingtank 58 and the abrasive delivery assembly 48.

The abrasive slurry may be widely varied. The abrasive slurry istypically formed by an abrasive and a fluid. The abrasive and fluid maybe selected from any suitable material or medium. By way of example, anabrasive such as Al₂O₃ or garnet and a fluid such as water may be used.The type of material selected depends on many factors including but notlimited to cutting ability and cost. Generally speaking, garnet providesgood cutting ability at reasonable cost while Al₂O₃ provides bettercutting ability at higher cost. The size of the abrasive used generallydepends on the size (diameter) of the opening in the nozzle. The size ofthe abrasive generally ranges between about 1/10 and about ½ thediameter of the opening in the nozzle, and more particularly about ¼ thediameter of the opening in the nozzle. Furthermore, the percentage ofabrasive to water (by weight) is generally between about 1% and about200%, more particularly between about 10% and about 100% and even moreparticularly about 40%.

The substrate 42 and cutting beam 44 are generally moved relative to oneanother in order to produce a linear cutting path (e.g., rectilinearand/or curvilinear). For example, the cutting beam 44 and/or thesubstrate 42 may be moved. The method of moving may be widely varied. Inthe illustrated embodiment, the singulation engine 40 includes a robotassembly 64 capable of moving the nozzle assembly 47. For example, therobot assembly 64 may include a transfer arm that is attached to themanifold 52 of the nozzle assembly 47. The robot assembly 64 may providelinear movements in the x, y and z directions as well as rotations aboutthe x, y and z axis. In most cases, the robot assembly 64 moves thenozzle assembly 47 within a single plane along a desired cutting path sothat all or any selected part of the substrate 42 may be cut by thecutting beam 44 (e.g., x, y and θ_(z)). When cutting integrated circuitpackages, the robot assembly 64 may make one or more passes in the xdirection and one or more passes in the y direction in order to cut thesubstrate 42 into integrated circuit packages (see FIGS. 2A, 3 and 4).The robot assembly 64 may also be arranged to move in a serpentinefashion. The robot assembly 64 may be widely varied. For example, therobot assembly 64 may consist of linear actuators (servos, steppers),SCARA robots and the like. In one particular embodiment, a SCARA robotassembly is used. By way of example, SCARA robot assemblies manufacturedby Epson Robots of Carson, Calif. may be used.

The singulation engine 40 also includes a chuck 66 configured to supportand hold the substrate 42 and the parts cut therefrom before, during andafter singulation. As shown, the chuck 66 includes one or more openings67 disposed therethrough. The openings 67 allow the cutting beam 44 toflow past the substrate 42, through the chuck 66, and to the slurrystored in the holding tank 58. The opening configuration generallyprovides a path that corresponds to the cutting path produced by therobot assembly 64. For example, it may be formed as a linear opening inthe x and/or y directions. The openings may include one large continuousopening or a plurality of discontinuous openings. A continuous openingtypically has the advantage that the cutting beam can follow its cuttingpath without being stopped. The width of the opening 67 is typicallylarger than the diameter of the cutting beam 44.

Any number of chucks may be used. For example, a single chuck forholding a single substrate, or a plurality of chucks for holding aplurality of substrates may be used. In one embodiment, a first chuckincludes openings for a cutting path in a first direction (e.g., x) anda second chuck includes openings for a cutting path in a seconddirection (e.g., y) that is orthogonal to the first direction. Theintegrated circuit packages may be singulated from the substrate byperforming a first cutting sequence in the first direction on the firstchuck and thereafter transferring the substrate to the second chuck andperforming a second cutting sequence in the second direction on thesecond chuck. The position of the first and second chucks relative toone another varies according to the specific needs of the singulationengine. In one embodiment, the chucks are positioned in line with oneanother. In another embodiment, the chucks are placed side by side.

The chuck 66 itself may be widely varied. For example, the chuck 66 maybe an electrostatic chuck, a mechanical chuck, a vacuum chuck or thelike. In the illustrated embodiment, the chuck 66 is configured toprovide a vacuum in order to hold the substrate 42 and packages before,after and during singulation. In this particular embodiment, the chuck66 includes a vacuum platform 68 and a vacuum manifold 70 disposedunderneath the vacuum platform 68. The vacuum platform 68 is generallyconfigured to receive the substrate 42 and the packages. For example,the vacuum platform 68 may be configured to receive the molded side ofthe substrate 42 (and package) so as to place the substrate 42 (andpackages) in an upwards position for singulation. The vacuum platform 68generally includes a plurality of openings (not shown), each of whichgenerally corresponds to one of the singulated packages. That is, thevacuum platform 68 includes an opening that applies a vacuum to eachpackage to be singulated. The vacuum manifold 70, on the other hand, isgenerally configured to supply a vacuum to each of the openings of thevacuum platform 68. In most cases, the vacuum manifold 218 includeschannels therein that fluidly couple the openings of the vacuum platform68 to a vacuum source 72. The vacuum manifold 70 is typically mounted toa base 74 that serves to support the chuck 66 in its position relativeto the other components of the singulation engine 40.

The singulation engine 40 may also include a controller 76 forcontrolling the various components of the singulation engine 40. Forexample, the controller 76 may include capabilities for, but not limitedto, controlling the movement of nozzle 50 via the robot assembly 64,controlling the flow of the slurry 60 via the pump 56, controlling thevacuum that holds the substrate 42 via the vacuum source 72, and thelike. The controller 76 may be arranged to act as an operator consoleand master controller of the system. That is, all system interfaces withan operator and the user's facilities may be made through thecontroller. Commands may be issued to and status may be monitored fromall components so as to facilitate completion of operator assignedtasks. By way of example, the controller may include a keyboard foraccepting operator inputs, a monitor for providing visual displays, adatabase for storing reference information, and the like.

In one embodiment, the controller 76 is configured to initiate a cuttingsequence. During the cutting sequence, the controller may cause thecutting beam to turn on and off while the nozzle and thus the cuttingbeam moves via the robot assembly. A continuous cutting sequence may beimplemented where the cutting beam is continuously produced while therobot assembly moves the nozzle along a path. During a continuouscutting sequence, for example, the cutting beam may be turned on whenmoving in a first direction (e.g., x) as well as a second direction(e.g., y). In addition, an incremental cutting sequence may beimplemented where the cutting beam is turned on and off incrementallywhile the robot assembly moves the nozzle along a path. During anincremental cutting sequence, for example, the cutting beam may beturned on when moving in a first direction (e.g., x) and turned off whenmoving in a second direction (e.g., y).

A method of producing integrated circuit packages (product by process)will now be discussed. By way of example, the integrated circuit packagemay be any one of those previously described. The method generallybegins by forming a plurality of integrated circuit packages on asubstrate. In the case of QFN packages, for example, the packages aregenerally formed in groups on a metal strip or carrier (e.g., copper).The metal strip is processed to include an exposed die attach pad and aplurality of peripheral terminal pads for each individual QFN package. Adie is generally attached to each of the die attach pads using aconventional die attach material. The die is also coupled to theplurality of peripheral terminal pads via a plurality of wires. A moldcompound is generally used to encase or surround portions of the die,wires, exposed peripheral terminal pads and the exposed die attach pad.The die itself is typically sandwiched between the mold compound and themetal strip. The mold compound helps to keep the wires and terminal padselectrically isolated from each other as well as to help protect thedie.

Once the packages are formed on the substrate, the substrate is cut witha cutting beam in order to separate the individual integrated circuitpackages from the substrate. This may be accomplished with the one ormore jet streams that are made incident on the surface of the substrateand that are configured to cut through the substrate as for example, themetal strip and mold compound of the QFN substrate.

The jet streams are generally configured to move in a manner that cutsthe integrated circuit packages as for example into rectangles orsquares (see for example, FIGS. 22A–J or FIGS. 23A–B).

The substrate may be cut using a variety of techniques. One suchtechnique will now be discussed with reference to FIG. 6. The substratesare typically received and loaded into the singulation engine, as forexample, at a loading dock of the singulation engine. Once received, thesubstrates 42 are placed on the chuck 66 by a transfer assembly (notshown). During placement, the substrates 42 are aligned to a referencesurface (e.g., alignment pins) and secured or held to the top surface ofthe chuck 66 using a suction force produced by the vacuum source 72.Thereafter, the nozzle assembly 47 is moved into a starting positionrelative to the substrate 42 held on the chuck 66. Once in position, theabrasive slurry delivery system 48 delivers the abrasive slurry to thenozzle assembly 47 and the abrasive slurry is subsequently squeezed outthe nozzles 50. The abrasive slurry is forced into a jet stream thatstrikes and cuts through the substrate 42 while the substrate 42 is heldby the chuck 66. The nozzle assembly and thus the jet stream is thenmoved along a cutting path via the robot assembly 64 in order toseparate the integrated circuit packages from the substrate. During thecutting sequence, the abrasive slurry in the jet stream is collected inthe holding tank 58 after passing through the substrate 42 and theopening 67 in the chuck 66.

FIGS. 7A and 7B are diagrams of a nozzle assembly 80, in accordance withone embodiment of the present invention. FIG. 7A is a front view, incross section, of the nozzle assembly 80 and FIG. 7B is a side view, incross section, of the nozzle assembly 80. By way of example, the nozzleassembly 80 may generally correspond to the manifold assembly 47 shownin FIG. 6. The nozzle assembly 80 generally includes one or more nozzles82 fluidly coupled to a nozzle manifold 84. In this particularconfiguration, the nozzle assembly 80 includes multiple nozzles 82 sothat multiple jet streams can be generated. As should be appreciated,multiple jet streams can reduce the amount of time needed to singulate asubstrate, i.e., more nozzles typically reduce the cycle time of thesystem. For example, each jet stream produced by each of the nozzles 82may be configured to cut a different group of packaged devices locatedon a substrate at the same time, for example, the four groups ofintegrated circuit packages located on the substrate shown in FIGS. 3Aand 3B.

As shown, the manifold 84 includes one or more first couplingreceptacles 85A configured to receive one or more first couplings 86A.The first couplings 86A are configured to receive a slurry distributiontube 87 from a slurry delivery assembly (e.g., assembly 48 in FIG. 6).The manifold 84 also includes one or more second coupling receptacles86B configured to receive one or more second couplings 86B. Each of thesecond couplings 86B are configured to receive an individual nozzle 82.A collar 90 may be used to hold the nozzle 82 relative to the end of thesecond couplings 86B.

The manifold 84 additionally includes a plurality of channels 92, 94, 96therein for fluidly connecting the first and second receptacles 85A and85B and thus the slurry delivery assembly to the nozzles 82. Thechannels may be widely varied. The channels generally include one ormore slurry receiving channels 92, a main channel 94 and one or moreslurry distribution channels 96. The slurry receiving channels 92connect the first coupling receptacles 85A to the main channel 94. Theslurry distribution channels 96 connect the second coupling receptacles85B to the main channel 94. The manifold 84 may also include one or morethrough holes 97 for attaching the manifold assembly 80 to a robotassembly.

During operation, the first couplings 86A, which are mounted in thefirst coupling receptacles 85A, receive slurry from the slurry tube 87and deliver the slurry to the slurry receiving channels 92. The slurryreceiving channels 92 receive slurry from the first couplings 86A anddeliver the slurry to the main channel 94. The main channel 94 receivesthe slurry from each of the slurry receiving channels 92 and deliversthe slurry to each of the slurry distribution channels 96. The slurrydistribution channels 96 receive the slurry from the main channel 94 anddelivers the slurry to the second couplings 86B. The second couplingsreceive the slurry from the slurry distribution channels 96 and deliversthe slurry to each of the nozzles 82. Thereafter, the slurry is forcedthrough the aperture 88 in the nozzle 82.

The couplings 86A, tube 87 slurry receiving channels 92 and main channel94 are generally large diameter so as to move large volumes ofpressurized slurry at very low speeds, preventing wear to the tubing,manifold and joints. By way of example, the diameter may be about 5 mm.The slurry distribution channels 96 and couplings 86B on the other handtypically have a smaller diameter. By way of example, the diameter maybe about 3 mm. The nozzles 82 themselves include a small diameteraperture 88. “Squeezing” the slurry through the small aperture 88 causesit to exit the nozzle 82 at very high speeds and in a fine diameter. Thesize of the nozzle aperture 88 is generally selected based on thedesired cutting width. The length of the aperture 88 is generallyconfigured to match the abrasive size and the desired beam diameter soas to cause the slurry to proceed through the nozzle 82 in an orderlyand predictable manner, i.e., becomes collimated. As should beappreciated, the nozzle aperture does not widen during use because theexiting beam is kept laminar and straight (and the lack of air in thepressurized stream). By way of example, the diameter of the nozzleaperture may be about 0.050 mm to about 3.0 mm, and more particularlybetween about 0.25 mm and about 0.3 mm. In addition, the length of thenozzle aperture may be between about 2D and about 20D, and moreparticularly between about 10D and about 15D, where D=the diameter ofthe nozzle aperture.

In one embodiment, the main channel 94 is formed by drilling a holeentirely through the manifold 84 from one side to the other and thencapping the hole with a set of plugs 98, and the slurry receiving andslurry distribution channels 92, 96 are formed by drilling holespartially through the manifold 84 from opposite sides of the manifold 84respectively to the main channel 94. The slurry receiving and slurrydistribution channels 92, 96 are generally perpendicular to the mainchannel 94. The manifold, couplings and nozzles are generally formedfrom a material that is resistant to the effects of the slurry flowingtherethrough. These components are generally formed from high hardnessmaterials such as stainless steel.

FIG. 8 is a side view, in cross section, of a nozzle 100. By way ofexample, the nozzle 100 may generally correspond to the nozzle 82 shownin FIGS. 7A and 7B. The nozzle 100 generally includes a nozzle tip 102attached to a nozzle body 104. The nozzle tip 102 includes an aperture105. The nozzle tip is preferably formed by a high hardness material inorder to minimize wear at the nozzle exit. In one embodiment, the nozzletip 102 is formed from stainless steel and the aperture 105 is formedfrom a diamond material. The aperture may also be formed from a carbidematerial. The diameter and length of the aperture 105 typically variesaccording to the specific needs of the device. As mentioned above, thediameter may be between about 0.05 mm and about 3.0 mm and the lengthmay be between about 2D and about 20D, where D=the diameter of thenozzle aperture.

The nozzle body 104 includes a tip receptacle 106 for receiving thenozzle tip 102 and a seat receptacle 108 for receiving the end of acoupling as for example coupling 86B of FIG. 7. The tip receptacle 106includes a slope that matches the nozzle tip 102 thus allowing thenozzle tip to seat therein. As shown, the nozzle tip may extend past thebottom surface of the nozzle body 104 when seated in the receptacle 106of the nozzle body 104. The seat receptacle 108 includes a slope thatmatches the end of the coupling thus allowing the end of the coupling toseat therein. The nozzle 100 also includes a retaining mechanism 110located above the nozzle tip 102. The retaining mechanism may be widelyvaried. In one embodiment, the nozzle body 104 is formed from stainlesssteel and the retaining mechanism 110 is formed from sintered metal. Asshown, the inner surfaces of the seat receptacle, retaining mechanismand nozzle tip inlet cooperate to form a conical entry point.

The dimensions of the nozzle 100 will now be described in accordancewith one embodiment. The slope of the seat receptacle is about 30degrees from center or 60 degrees in total. The slope of the tipreceptacle is about 11 degrees from center or 22 degrees in total. Thenozzle body is about 9.5 mm in length and has about a 12 mm diameter atits widest section and about 9 mm diameter at its thinnest section. Theseat receptacle opening is about 7.8 mm and the diameter of the aperture105 is about 0.300 mm±0.003 mm. The nozzle tip is about 4 mm in lengthand the aperture is about 3 mm in length. Furthermore, the diamondnozzle extension distance (the distance between surfaces of the body andthe tip) is may be about 0.1-0.5 mm.

FIG. 9 is a side elevation view, in cross section, of an abrasive slurrydelivery assembly 112, in accordance with one embodiment of the presentinvention. By way of example, the abrasive slurry delivery assembly 112may generally correspond to the abrasive slurry delivery assembly shownin FIG. 6. The abrasive slurry delivery assembly 112 generally includesa slurry containment vessel 114, a fluid source 116 and an abrasivesource in the form of an abrasive cartridge 118. The slurry containmentvessel 114 is configured to contain an abrasive slurry 120 for use by asingulation engine. The abrasive slurry 120 generally contains a fluidsuch as water and an abrasive such as garnet. The slurry vessel 114receives the fluid from the fluid source 116 and the abrasive from theabrasive cartridge 118 through a recharge valve 122 located at the topof the slurry containment vessel 114. In order to supply the abrasiveslurry 120 to a nozzle assembly of a singulation engine, the slurrycontainment vessel 114 is pressurized and the abrasive slurry 120 isreleased through a port 124 located in the bottom of the slurrycontainment vessel 114 (or a tubing connected the top of vessel 114).

The slurry containment vessel 114 is pressurized by a high pressure pump126. The manner in which the high pressure pump 126 builds pressure maybe widely varied. In the illustrated embodiment, the high pressure pump126 pumps a fluid from the fluid source 116 into the slurry containmentvessel 114 until the slurry containment vessel 114 is adequatelypressurized. By way of example, the slurry containment vessel may bepressurized between about 1,000 PSI and about 50,000 PSI.

The abrasive cartridge 118 is configured to supply new abrasive materialto the assembly 112. When emptied, the abrasive cartridge 118 is removedfrom the assembly 112 and a new abrasive cartridge 118 filled with newabrasive material is inserted into the assembly 112. This particularmethod prevents contaminants from entering the singulation engine. Theabrasive material filled in the cartridge 118 may be wet or dry. In theillustrated embodiment, however, the cartridge is prefilled with onlythe dry abrasive material. This is done to reduce the weight of thecartridge 118 so that it can be easily handled by an operator. Once thecartridge 118 is connected to the assembly 112, a fluid may beintroduced into the cartridge 118 in order to “wet” the dry abrasivethereby helping to reduce air in the system. As should be appreciated,the lack of air in the pressurized stream helps prevent the nozzleaperture from widening. The fluid may also help move the wet abrasive(slurry) to the slurry containment vessel.

As shown in FIG. 9, a diaphragm pump 128 is used to both feed a fluidinto the abrasive cartridge 118 in order to “wet” the abrasive materialand to force the “wet” abrasive material to the slurry containmentvessel 114. The diaphragm pump generally operates at low pressure, asfor example between about 1 PSI and about 75 PSI. The diaphragm pump 127may receive the fluid directly from a fluid source or it may receive thefluid indirectly from the slurry containment vessel 114 as shown. Inoperation, the diaphragm pump 127 pumps the fluid into the cartridge 118thereby allowing the fluid to mix with the abrasive and forcing the wetabrasive from the cartridge 118 into the vessel 114 through the rechargevalve 122. In order to flush and drain the components of the assembly112, the assembly 112 may include a flush water valve 128 forintroducing a fluid into the assembly 112, and a drain 129 to remove airor fluid from the system.

An operational sequence of the abrasive slurry delivery assembly 112will know be discussed in accordance with one embodiment. The sequencegenerally begins by opening the flush water valve 128 in order tointroduce water into the cartridge 118. Once the cartridge 118 is filledwith water, the flush water valve 128 is closed. Thereafter, therecharge valve 122 of the slurry containment vessel 114 is opened. Onceopened, the diaphragm pump 128 is activated thereby causing the abrasiveto be sucked from cartridge 118 to the slurry containment vessel 114.Once the containment vessel 114 is full of abrasive, the flush watervalve 128 is opened in order to clean the hose and recharge valve 122.After the system is cleaned, the diaphragm pump 128 is deactivated,i.e., shuts down, and the recharge valve 122 and flush valve 128 areclosed. The abrasive slurry delivery assembly 112 is now ready to pumpthe abrasive to the nozzle assembly. In particular, the high pressurepump 126 is activated thereby pressurizing the slurry containment vesseland forcing the abrasive slurry 120 out of the slurry containment vessel114 and into the nozzle assembly.

FIG. 10 is a simplified side view of a wet slurry filter arrangement130, in accordance with one embodiment of the present invention. By wayof example, the filter arrangement 130 may be used in a re-circulatorydelivery assembly between the holding tank and the vessel (see FIG. 6).The filter arrangement 130 includes a plurality of filter elements 132,which are layered one on top of the other. Each filter element 132includes a container 134 and a filter 136. The filter 136 is configuredto separate the container 134 into first and second chambers 138 and140. The filter 136 is preferably designed to allow good abrasivematerial to flow from the first chamber 138 into the second chamber 140while preventing oversized abrasive material or contaminant materialfrom flowing therethrough (e.g., oversized material). This is generallyaccomplished with mesh screen having a plurality of openings 142dimensioned similarly to the size of the good abrasive material, i.e.,particles in the slurry that are smaller than size of the opening passthrough the openings 142 while particles that are larger than the sizeof the openings 142 are blocked from passing through the openings. Inessence, the oversized material is retained in the first chamber 138 andthe good material is retained in the second chamber 140. By way ofexample, the size of the openings may be between about 20 mesh and about500 mesh, and more particularly between about 100 mesh and about 150mesh.

In order to utilize the wet slurry filter arrangement 130, each filterelement 132 includes a used slurry inlet 142 for receiving used slurry.For example, a slurry that has been previously used to cut through asubstrate. As should be appreciated, used slurry may contain particlesfrom the cut substrate. The used slurry inlet 142 is located in thefirst chamber 138 thereby allowing the used slurry to be introduced intothe first chamber 138. Each filter element 132 also includes anoversized slurry outlet 144 and a good slurry outlet 146. The bad slurryoutlet 144 is located in the first chamber 138 and the good slurryoutlet 146 is located in the second chamber 140. The outlets 144 and 146are generally positioned opposite the inlet 142, i.e., the inlets andoutlets are on opposing ends of the filter element. During operation,the used slurry is introduced into the first chamber 138. As it passesfrom one end of the first chamber 138 to the other end of the firstchamber 138, the good slurry drops through the filter 136 into thesecond chamber 140. Once in the second chamber 140, the good slurryexits out of the good slurry outlet 146. The good slurry from each ofthe good slurry outlets 146 are combined and reintroduced back into thesystem. The slurry left in the first chamber 138 exits out of the badslurry outlet 144. The bad slurry from each of the filtering elements132 are combined and removed from the system.

Because the particles are small, the size of each of the filterarrangements can be small. By way of example, each of the filterarrangements may have a length (from opposing sides) between about 300to about 600 mm, a width between about 100 to about 400 mm and a heightbetween about 20 to about 200 mm. As should be appreciated, multiplefiltering elements can be layered on top of each other to increase thespeed that the slurry is filtered. By way of example, the wet slurryfilter arrangement 130 may include 2 to about 20 filter elements.

FIG. 11 is top view of a chuck assembly 150, in accordance with oneembodiment of the present invention. The chuck assembly 150 is generallyconfigured to hold an unsingulated substrate and the singulatedintegrated circuit packages cut therefrom before, during and after asingulation procedure carried out with a cutting beam. The chuckassembly 150 generally includes a chuck 152 having a plurality ofopenings 154 and a plurality of slots 156. The openings 154 provide avacuum therethrough so as to hold the substrate thereon. The slots 156provide a passageway through which a jet stream may pass when cuttingthe substrate. By way of example, the chuck 152 may generally correspondto the chuck shown in FIG. 6.

The configuration of the openings 154 and slots 156 may be widelyvaried. In general, the chuck 152 includes one or more groups ofopenings 154 that are arrayed in rows and columns. The slots 156 arespatially separated from the openings 154 and are typically positionedin either rows or columns alongside the openings 154. In the illustratedembodiment, the slots 156 are positioned in columns. In most cases,there is a slot 156 outside the first and last column or rows ofopenings 154 and between each row and column of openings 154. The slots156 may include starter holes 158. The starter holes 158 provide a placewhere a cutting path can begin. The configuration and number of starterholes 158 generally depends on the configuration of packages formed onthe substrate (e.g., number of groups, package spacing, etc.), thenumber of nozzles used to cut the substrate (e.g., single, multiple) andthe cutting sequence used to cut the substrate (e.g., continuous,incremental, etc.).

The chuck assembly 150 may include any number of chucks 152. When usinga single chuck, a first set of linear cuts may be performed when thesubstrate is in a first position relative to the chuck and a second setof linear cuts may be performed when the substrate is in a secondposition relative to the chuck. For example, the substrate may berotated between sets of cuts in order to make orthogonal cuts on thesubstrate. Although the cutting path is in a single direction,multidirectional cuts on the substrate may be performed thereby leavinga plurality of square or rectangle packages. When using multiple chucks,a first set of linear cuts may be performed in a first direction on afirst chuck and a second set of linear cuts may be performed in a seconddirection on a second chuck. In this implementation, the position of theslots generally depends on the direction of the cuts being performed onthe chuck. For example, if the chuck is configured for x axis cuttingthen the slots are situated in the x direction (columns), and if thechuck is configured for y axis cutting then the slots are situated inthe y direction (rows).

Although only one chuck configuration is shown in FIG. 11, it should benoted that this is not a limitation and that other configurations may beused. For example,

FIGS. 12A–12C each show different configurations of a chuck. In FIG.12A, each slot 156 includes a starter hole 158 and all of the starterholes 158 are on the same side of the slots 156. In FIG. 12B, each slot156 includes a starter hole 158, however, the starting holes 158alternate back and forth between opposing sides of the slots 156. InFIG. 12C, the slot is formed by one continuous slot rather than aplurality of spatially separated slots (e.g., serpentine configuration).

FIG. 13 is a perspective view of a chuck assembly 200, in accordancewith one embodiment of the present invention. By way of example, thechuck assembly 200 may correspond to the chuck shown in FIG. 6. Thechuck assembly 200 is generally configured to hold an unsingulatedsubstrate and the singulated integrated circuit packages cut therefrombefore during and after a singulation procedure carried out with acutting beam. The chuck assembly 200 generally includes a first chuck202 and a second chuck 204. The first chuck 202 is configured to hold asubstrate (and the integrated circuit packages formed therefrom) duringy axis cutting, and the second chuck 204 is configured to hold thesubstrate (and the integrated circuit packages formed therefrom) duringx axis cutting. For a given substrate, the substrate is typically cut ina first direction, as for example the y direction, and thereafter it iscut in a second direction, as for example the x direction. As should beappreciated, this cross cutting technique is configured to cut rectangleor square integrated circuit packages from the substrate.

A typical sequence may include, placing a substrate on the first chuck202, making multiple cuts in the y direction on the first chuck 202,thereafter transferring the substrate to the second chuck 204, and thenmaking multiple cuts in the x direction on the second chuck 204. Thecuts may be made by one or more cutting beams that are moved in the xand y directions via a robot assembly. Furthermore, the transferring maybe accomplished with some sort of pick and place machine that uses pickdevices to pick and place the substrate and a robot assembly to move thesubstrate.

Each of the chucks 202 and 204 is supported on a base 206, and includesa vacuum platform 208 and a vacuum manifold 210. As shown, the vacuumplatform 208 is disposed on the vacuum manifold 210 and the vacuummanifold 210 is disposed on the base 206. These components areconfigured to work together to hold the substrate and the integratedcircuit packages cut therefrom with a vacuum. These components are alsoconfigured to work together to allow a cutting beam to be directedtherethrough in the z direction. These components may be attached usingany suitable means.

Referring to FIG. 14, the chuck assembly 200 will be described ingreater detail. The vacuum platform 208 is configured to receive thesubstrate thereon. The vacuum platform 208 includes a plurality ofopenings 212 that provide a vacuum therethrough so as to hold thesubstrate thereon. The openings 212 may be widely varied. The openingconfiguration and size generally depends on the size of the substrateand the size and number of integrated circuit packages cut therefrom. Inmost cases, there is an opening for each integrated circuit package.Furthermore, the openings are typically grouped in rows and columns. Therows and columns may be part of one or more groups. In the illustratedembodiment, the rows and columns are separated into four groups. By wayof example, these four groups may correspond to the four groups shown onthe substrate in FIG. 3B.

The vacuum platform 208 also includes a plurality of slots 214 thatprovide a space through which a cutting beam may pass when cutting alongthe x and y axis. The slots 214 are generally positioned in the spacebetween the openings 212. The position of the slots 214 generallycoincide with the saw streets of the substrate, i.e., the space betweenthe integrated circuit packages that is dedicated for cutting. The pathof the slots 214 may be oriented in a single direction (e.g., x or y) orthey may be bidirectional (e.g., x and y). In the illustratedembodiment, the slots on each of the chucks are oriented in a singledirection. Although similar in most respects, each of the chucks 208 isconfigured to serve different cutting directions, and therefore theslots 214 are positioned in different directions on the vacuum platforms208 of the two chucks 202 and 204. As shown, the slots 214A arepositioned linearly in the y direction in the first chuck 202, and theslots 214B are positioned linearly in the x direction in the secondchuck 202.

Each of the vacuum platforms 208 also include one or more alignment pins216 for aligning the substrate on the vacuum platforms 208. Thealignment pins 216 are generally configured to extend into alignmentholes in the substrate.

Similarly to the vacuum pedestals 208, the vacuum manifolds 210 includea plurality of slots 218 that provide a space through which a jet streammay pass when cutting along the x and y axis. The position of the slots218 in the vacuum manifold 210 generally coincide with the position ofthe slots 214 in the vacuum platform 208, i.e., they have a similar sizeand direction, and they are aligned when the vacuum platform 208 isattached to the vacuum manifold 210.

The vacuum manifolds 210 also include a plurality of vacuum channels 222configured to provide a vacuum passageway to the openings 212 of thevacuum pedestals 208. The channels 222 may be widely varied. The channelconfiguration and size generally depends on the size and configurationof the vacuum pedestal openings 212 as well as the direction of theslots 214/218. In the illustrated embodiment, there is a channel 222 foreach row or column of openings 212. The channels 222 typically runlinearly between the slots 214/218. As such, the channels 222A in thevacuum manifold 210A of the first chuck 202 run in the y direction, andthe channels 222B in the in the vacuum manifold 210B of the second chuck204 run in the x direction. The channels 222 are typically coupled to amain channel 224 that intersects one or more openings 226 that extendthrough the vacuum manifolds 210. The openings 226 are configured tomate with a coinciding set of openings 228 in the base 206 of the chuckassembly 200. These openings run through the base 206 and couple tovacuum fittings 230, which couple to a vacuum source via vacuum tubing(not shown).

The base 206 is configured to support the chucks 202 and 204 in theirdesired position relative to each other and relative to a singulationengine such as for example the singulation engine shown in FIG. 6. Thebase 206 includes a pair of voids 232, each of which is disposedunderneath one of the chucks 202 and 204. The voids 232 provide a spacethrough which a jet stream may pass when cutting along the x and y axis,i.e., through the slots 214/218. The portion of the base 206 thatsurrounds the voids 232 serves as a point for connecting the chucks 202and 204 to the base 206. The periphery of the voids 232 is smaller thanthe periphery of the chucks 202 and 204 and thus the base 206 provides ashoulder 234 for which the chucks 202 and 204 may rest or be attached.

The vacuum platform 208 or portions thereof may be formed from variousmaterials, including but not limited to, deformable and/or rigidmaterials. By way of example, the vacuum platform may be formed frommaterials such as ceramic, metal, plastic, rubber and/or the like. Itmay be preferable that the vacuum platform 208 be formed from materialsthat are capable of withstanding the rigors of a jet stream cuttingsequence. Alternatively or additionally, it may be preferable that thevacuum platform material be able to withstand, for a commerciallysatisfactory number of cycles, the de-ionized water rinsing process thatmay be employed before, during and after cutting. Alternatively oradditionally, it may be preferable that the vacuum platform materialpossess anti-static properties to prevent damage to the integratedcircuits being fabricated. Alternatively or additionally, it may bepreferable that the vacuum platform material possess a high frictioncoefficient relative to the undersurface of the substrate to preventtranslational and/or rotational movement of the substrate and/or theindividual packages during and after cutting. Alternatively oradditionally, it may be preferable that the vacuum platform materialprovide a surface with sealing capabilities. For example, when a vacuumis applied to the package through the vacuum opening, the surfacecontacting the package deforms to the edge of the package therebysealing the interface between the surface of the vacuum platform and thesurface of the package.

In one embodiment, the vacuum platform is formed from a rubber likematerial such as “VITON” a synthetic material available from McDowell &Company of Downey, Calif. or Pacific State Felt & Mfg. Co. Inc. ofHayward Calif. The resilient VITON material, in addition to beingconformable and/or compressible, also offers substantial advantages withrespect to machinability, high friction, anti-static property, relativeinertness to the rinsing chemicals, and general durability when employedin the vacuum platform application. Although the term “rubberized” isused, it should be noted that the vacuum platform is not limited torubber materials and that the term “rubberized” is used to referencesome of the above mentioned properties (e.g., sealing). In anotherembodiment, the vacuum platform is formed from stainless steel such asCorrax stainless steel. The steel may have a hardness between about48–50 RC. In yet another embodiment, the vacuum platform may be formedfrom a combination of materials. For example, the vacuum platform mayinclude a top layer formed from VITON and a lower layer formed fromstainless steel.

The vacuum manifold may be formed from similar materials as the vacuumplatform, as for example ceramics, metal, plastics, rubber and the like.In one embodiment, the vacuum manifold is formed from stainless steel.By way of example, the stainless steel may be Corrax stainless steel.The steel may have a hardness between about 48–50 RC.

The vacuum platform and manifolds may be formed using any suitabletechnique including but not limited to machining, molding and the like.For example, when using stainless steel, the openings and the slots maybe formed by EDM. When using a rubber like material, the slots may beformed by the cutting beam of the singulation engine during an initialcutting sequence. That is, the cutting beam may be used to cut throughthe material and form the requisite slots therein. The vacuum pedestalmay be attached to the vacuum manifold using any suitable attachmentmeans including but not limited to conventional fasteners such as bolts,adhesives, welding, clamps, and the like. When using a rubberized vacuumpedestal, the vacuum pedestal may be attached to the vacuum manifold viaan adhesive such as glue or epoxy. The vacuum pedestal/manifoldcombination can be fastened to the base via one or bolts.

Referring to FIGS. 15 and 16, the chucks 202 and 204 will be describedin greater detail. In both these Figures, a substrate S is being held tothe chuck 202 or 204 during a cutting sequence. The substrate istypically aligned with the chuck 202 or 204 via alignment pins 216. Asshown in FIG. 15, the vacuum platform 208 includes a vacuum opening 212for each package P and thus the entire substrate S as well as eachindividual package P being cut therefrom is held on the vacuum platform208 before, during and after singulation via a suction force (e.g.,vacuum). To elaborate, the vacuum platform 208 is positioned over thevacuum manifold 210 and each row (or column) of openings 212 is locatedover a vacuum channel 222 in the vacuum manifold 210. Each vacuumchannel 222 connects to the main channel 224 of the vacuum manifold 210and the main channel 224 connects to the opening 226 of the vacuummanifold 210. Moreover, the vacuum manifold 210 is positioned over thebase 206 and the opening 226 of the vacuum manifold mates with theopening 228 of the base 206. The opening 228 runs through the base 206and couples to a vacuum source via vacuum tubing and vacuum fittings(not shown). When the vacuum source is turned on, a suction force ispulled through the previously mentioned vacuum passageways (as shown bythe arrows) in order to secure the substrate S and individual package Pbeing cut therefrom to the surface of the vacuum platform 208.

As shown in FIG. 16, the vacuum platform 208 includes a slot 214 that isaligned with a corresponding slot 218 of the vacuum manifold 210. Theslots 214/218 cooperate to form an opening 219 in the chuck 202 or 204.The opening 219 is positioned over the void 232 in the base 206. Thelength of the opening 219 is typically the same size or smaller than thelength of the void 232. During the cutting sequence, the jet stream JScuts through the substrate and passes through opening 219 of the chuck202 or 204 and the void 232 of the base 206. After passing through thevoid 132, the jet stream JS may be diffused in a holding tank asdiscussed previously. In addition, the jet stream JS moves linearly tothe right through the opening 219 in order to form a linear cut C in thesubstrate S. By way of example, the jet stream JS may be moved in the xor y direction depending on the chuck being used.

Although not shown in either FIG. 15 or 16, the top layer of the vacuumplatform 208 may include a deformable material so as to provide a sealbetween the top surface of the vacuum platform 208 and the bottomsurface of the substrate S and individual package P being cut therefromwhen the suction force is supplied. The top layer may be a continuousportion of the vacuum platform 208 or it may be a separate componentadhered thereto. A seal may also be provided between each of the variouslayers of the chucks 202 and 204 in order to seal the vacuumpassageways.

FIGS. 17A–F are diagrams of a vacuum platform 250, in accordance withone embodiment of the present invention. The vacuum platform 250 isconfigured to allow linear cuts in the y direction. As such, the vacuumplatform 250 may generally correspond to the vacuum platform 208A shownin FIGS. 13 and 14. To elaborate, FIG. 17A is a perspective view of thevacuum platform 250, FIG. 17B is a top view of the vacuum platform 250,FIG. 17C is a front view, in cross section (taken along line C–C′), ofthe vacuum platform 250, FIG. 17D is a side view, in cross section(taken along line D–D′), of the vacuum platform 250, FIG. 17E is a sideview, in cross section (taken along line E–E′), of the vacuum platform250 and FIG. 17F is a close up front view, in cross section, of aportion of the rubber like vacuum platform 250.

As shown, the vacuum platform 250 includes a plurality of openings 252and a plurality of slots 254. Each of the openings 252 is formed by twoparts, a recessed or countersunk portion 256 and a through hole 258. Therecessed portion 156 has a greater diameter than the through hole 258,but is smaller than the periphery of the package. Although not arequirement, the openings 252 are positioned in four groups 260. Thegroups 260 include openings 252 that are arrayed in columns 262 and rows264. The number of rows 264 and columns 262 in each group 260 may bewidely varied. In the illustrated embodiment, there are 7 rows and 7columns.

The slots 254 are positioned in the y direction between each column 262.The slots 254 are also positioned outside the first and last column ofeach group 260. The slots 254 generally extend further than the firstand last opening in the columns 262. The first slot in each group (theone that is outside the first column of openings) extends even furtherthan the rest of the slots so as to connect to a starter hole 266. Thestarter hole 266 provides a starting point for when the jet stream isturned on. For example, a cutting sequence generally begins by placingthe centerline of the nozzle over the starter hole 266 before making anylinear cuts. The diameter of the starter hole 266 is generally biggerthan the width of the slot 254. The slot 254 is generally slightlylarger than the width of the jet stream.

FIGS. 18A–E are diagrams of a vacuum platform 270, in accordance withone embodiment of the present invention. The vacuum platform 270 isconfigured to allow linear cuts in the x direction. As such, the vacuumplatform 270 may generally correspond to the vacuum platform 208B ofFIGS. 13 and 14. To elaborate, FIG. 18A is a perspective view of thevacuum platform 270, FIG. 18B is a top view of the vacuum platform 270,FIG. 18C is a front view, in cross section (taken along line C–C′), ofthe vacuum platform 270, FIG. 18D is a side view, in cross section(taken along line D–D′), of the vacuum platform 270, and FIG. 18E is aportion, in cross section, of the vacuum platform 270.

As shown, the vacuum platform 270 includes a plurality of openings 272and a plurality of slots 274. Each of the openings 272 is formed by twoparts, a recessed or countersunk portion 276 and a through hole 278. Therecessed portion 276 has a greater diameter than the through hole 278,but is smaller than the periphery of the package so that the package maybe retained by a suction force. Although not a requirement, the openings272 are positioned in four groups 270. The groups 270 include openings272 that are arrayed in columns 272 and rows 274. The number of rows 274and columns 262 in each group 270 may be widely varied. In theillustrated embodiment, there are 7 rows and 7 columns.

The slots 274 are positioned in the x direction between each row 284.The slots 274 are also positioned outside the first and last rows ofeach group 280. The slots 274 generally extend further than the firstand last opening 272 in the row 284. The first slot in each group (theone that is outside the first row of openings) is coupled to a starterhole 286 via a starter slot 288 that is perpendicular to the first slot.The starter hole 286 provides a starting point for when the jet streamis turned on. For example, a cutting sequence generally begins byplacing the centerline of the nozzle over the starter hole 286 beforemaking any linear cuts. The diameter of the starter hole 286 isgenerally bigger than the width of the slot 274. The slot 274 isgenerally a slightly larger than the width of the jet stream.

FIGS. 19A–E are diagrams of a rubber like vacuum platform 240, inaccordance with one embodiment of the present invention. By way ofexample, the rubber like vacuum platform 240 may generally correspond toany of the vacuum platforms 208A or 208B shown in FIGS. 13 and 14. Therubber like vacuum platform 240 is shown before the slots have beenformed therein. As mention previously, the slots may be formed with ajet stream of the singulation engine. For example, the rubber likevacuum platform 240 may be attached to a vacuum manifold, and thereaftercut via the jet stream while in the singulation engine. In oneembodiment, the rubber like vacuum platform is formed from VITON.

To elaborate, FIG. 19A is a perspective view of the rubber like vacuumplatform 240, FIG. 19B is a top view of the rubber like vacuum platform240, FIG. 19C is a front view, in cross section (taken along line C–C′),of the rubber like vacuum platform 240, FIG. 19D is a side view, incross section (taken along line D–D′), of the rubber like vacuumplatform 240, and FIG. 19E is a close up front view, in cross section,of a portion of the rubber like vacuum platform 240. As shown in all theFigures, the rubber like vacuum platform 240 includes a plurality ofopenings 242. Each of the openings 242 is formed by two parts, arecessed or countersunk portion 244 and a through hole 246. The recessedportion 244 has a greater diameter than the through hole 146, but issmaller than the periphery of the package.

FIGS. 20A–F are diagrams of a vacuum manifold 290, in accordance withone embodiment of the present invention. The vacuum manifold 290 isconfigured to allow linear cuts in the y direction. As such, the vacuummanifold 290 may generally correspond to the vacuum manifold 210A shownin FIGS. 13 and 14. To elaborate, FIG. 20A is a perspective view of thevacuum manifold 290, FIG. 20B is a top view of the vacuum manifold 290,FIG. 20C is a front view, in cross section (taken along line C–C′), ofthe vacuum manifold 290, FIG. 20D is a side view, in cross section(taken along line D–D′), of the vacuum manifold 290, FIG. 20E is a sideview, in cross section (taken along line E–E′), of the vacuum manifold290 and FIG. 20F is a portion, in cross section, of the vacuum manifold290.

As shown, the vacuum manifold 290 includes a plurality of channels 292and a plurality of slots 294. Both the channels 292 and the slots 294are positioned in the y direction. Although not a requirement, thechannels 292 are positioned in four groups 302. The number of channels292 in each group 302 may be widely varied. The number of channels 292generally corresponds to the number of columns of openings found in thevacuum platform, which connects to the vacuum manifold 290. That is, thechannels 292 are configured to coincide with the openings of the vacuumplatform so as to provide a suction force therethrough. Each of thechannels 292 fluidly couples to a corresponding column of openings inthe vacuum platform. In the illustrated embodiment, there are 7 columns.In order to provide a vacuum to the channels 292, each of the channels292 fluidly couples to a main channel 304, which in turn couples to apair of openings 306. The channels 300 and 304 are recessed within thetop surface of the vacuum manifold 290 while the openings 306 extendthrough the vacuum manifold 290.

The slots 294 are positioned between each channel 292. The slots 294 arealso positioned outside the first and last channel 292 of each group302. The slots 294 generally extend further at the one end compared tothe channels 292. The first slot in each group (the one that is outsidethe first channel) extends even further than the rest of the slots so asto connect to a starter hole 308. The starter hole 308 provides astarting point for when the jet stream is turned on. For example, acutting sequence generally begins by placing the centerline of thenozzle over the starter hole 308 before making any linear cuts. Thediameter of the starter hole 308 is generally bigger than the width ofthe slot 294. The slot 294 is generally slightly larger than the widthof the jet stream. As should be appreciated, the position, and size ofthe slots 294 in the vacuum manifold 290 generally coincides with theposition and size of the slots in the mating vacuum platform, i.e., theyare aligned such that they form a unified slot.

FIGS. 21A–G are diagrams of a vacuum manifold 310, in accordance withone embodiment of the present invention. The vacuum manifold 310 isconfigured to allow linear cuts in the x direction. As such, the vacuummanifold 310 may generally correspond to the vacuum manifold 210B shownin FIGS. 13 and 14. To elaborate, FIG. 21A is a perspective view of thevacuum manifold 310, FIG. 21B is a top view of the vacuum manifold 310,FIG. 21C is a front view, in cross section (taken along line C–C′), ofthe vacuum manifold 310, FIG. 21D is a front view, in cross section(taken along line D–D′), of the vacuum manifold 310, FIG. 21E is a sideview, in cross section (taken along line E–E′), of the vacuum manifold310, FIG. 21F is a side view, in cross section (taken along line F–F′),of the vacuum manifold 310, and FIG. 21G is a portion, in cross section,of the vacuum manifold 310.

As shown, the vacuum manifold 310 includes a plurality of channels 312and a plurality of slots 314. Both the channels 312 and the slots 314are positioned in the y direction. Although not a requirement, thechannels 312 are positioned in two groups 316. The number of channels312 in each group 316 may be widely varied. The number of channels 312generally corresponds to the number of rows of openings found in thevacuum platform, which connects to the vacuum manifold 310. That is, thechannels 312 are configured to coincide with the openings of the vacuumplatform so as to provide a suction force therethrough. Each of thechannels 312 fluidly couples to a corresponding column of openings inthe vacuum platform. In the illustrated embodiment, there are 7 columns.In order to provide a vacuum to the channels 312, each of the channels312 fluidly couples to a main channel 318, which in turn couples to apair of openings 320. The channels 312 and 318 are recessed within thetop surface of the vacuum manifold 310 while the openings 320 extendthrough the vacuum manifold 310.

The slots 314 are positioned between each channel 312. The slots 314 arealso positioned outside the first and last channel 312 of each group316. The first slot in each group (the one that is outside the firstchannel) is coupled to a starter hole 322 via a starter slot 324 that isperpendicular to the first slot. The starter hole 322 provides astarting point for when the jet stream is turned on. For example, acutting sequence generally begins by placing the centerline of thenozzle over the starter hole 322 before making any linear cuts. Thediameter of the starter hole 322 is generally bigger than the width ofthe slot 314. The slot 214 is generally slightly larger than the widthof the jet stream. As should be appreciated, the position, and size ofthe slots 314 in the vacuum manifold 310 generally coincides with theposition and size of the slots in the mating vacuum platform, i.e., theyare aligned such that they form a unified slot.

FIGS. 22A–J illustrate a cutting sequence using the gang manifoldassembly 80 shown in FIGS. 7A and 7B and the chuck assembly 200 shown inFIGS. 13 and 14. The sequence generally begins by placing a substrate350 on the chuck 202 as shown in FIG. 22A. This is generallyaccomplished manually or using some sort of pick and place machine (notshown). During placement, the substrate 350 is positioned on the surfaceof the vacuum platform 208A and the substrate 350 is aligned relative tothe chuck 202 via alignment pins 216. After placement, the vacuum isturned on, and the substrate 350 is held in place by a suction force.The suction force is generated through the openings 212 of the vacuumplatform 208A, and the channels (not shown) of the vacuum manifold 210A.As shown in FIG. 22A, the substrate 350 includes a plurality ofintegrated circuit packages 352 formed thereon. By way of example, theintegrated circuit packages 352 may be QFN packages.

Once the substrate 352 is fixed by the suction force, the gang manifoldassembly 80 moves into its starting position over the chuck 202 as shownin FIG. 22B. This is generally accomplished by an x, y, z robot thatmoves the gang manifold 80 from an initial position to the cuttingposition. By way of example, the manifold 84 of the gang manifoldassembly 80 may be attached to a transfer arm 356 of a robot system. Asshown, the gang manifold 80, and more particularly the nozzles 82 arepositioned in close proximity to the surface of the substrate 350. Thatis, the robot moves the gang manifold 80 in the z direction until thenozzles 82 reach a specified cutting height, which is generally veryclose to the substrate. In most cases, the starting position in the xand y directions is defined by starter hole (not shown) on the chuck202.

While maintaining the suction force, the gang manifold assembly 80begins to make linear cuts 360 on the substrate 350 in the y directionas shown in FIGS. 22C and 22D. This is generally accomplished by turningon the jet stream (not shown) and moving the gang manifold in the ydirection via the robot system. The movement of the gang manifoldassembly 80 may be widely varied. In general, the nozzles 82 are movedtogether along a linear path so that multiple linear cuts 360 are made.Although only one linear cut 360 can be made with a single nozzle 82 atany one time, the surface of the substrate 350 is sequentially exposedto the jet stream in order to make multiple cuts. The nozzles may makeone pass in the y direction and then step over in the x direction inorder to make another pass in the y direction. The linear cuts 360generally extend from the edge of the first package 362 to the edge ofthe last package 364 in the group. In one embodiment, a serpentine path,which moves back and forth in the direction of the y-axis while beingincremented in the x-direction at the end of each traverse, may be used.In this particular embodiment, the movements in the x direction areperformed at high speeds so that the jet stream is prevented fromcutting through the substrate. This embodiment will be described ingreater detail below.

After making the final linear cut, the gang manifold assembly 80 movesaway from the chuck 202 and the vacuum is turned off thereby releasingthe suction force that had been holding the substrate 350. Thereafter,the cut substrate 350 is removed from the chuck 202 and placed on thesecond chuck 204 as shown in FIGS. 22E and 22F. This is generallyaccomplished manually or using some sort of pick and place machine (notshown). During placement, the substrate 350 is positioned on the surfaceof the vacuum platform 208B and the substrate 350 is aligned relative tothe chuck 204 via alignment pins 216. After placement, the vacuum isturned on, and the substrate 350 is held in place by a suction force.The suction force is generated through the openings 212 of the vacuumplatform 208B, and the channels (not shown) of the vacuum manifold 210B.

Once the substrate 350 is fixed by the suction force, the gang manifoldassembly 80 moves into its starting position over the chuck 204 as shownin FIG. 22B. This is generally accomplished by an x, y, z robot thatmoves the gang manifold 80 from either the initial position or the firstcutting position to a second cutting position. Similarly to the above,the gang manifold 80, and more particularly the nozzles 82 arepositioned in close proximity to the surface of the substrate 350. Thatis, the robot moves the gang manifold 80 in the z direction until thenozzles 82 reach a specified cutting height. In most cases, the startingposition in the x and y directions is defined by starter hole (notshown) on the chuck 104.

While maintaining the suction force, the gang manifold assembly 80begins to make linear cuts 366 on the substrate 350 in the x directionas shown in FIGS. 22H and 22I. This is generally accomplished by turningon the jet stream (not shown) and moving the gang manifold assembly 80in the x direction via the robot system. The movement of the gangmanifold assembly 80 may be widely varied. In general, the nozzles 82are moved together along a linear path so that multiple linear cuts 366are made. Although only one linear cut 366 can be made with a singlenozzle 82 at any one time, the surface of the substrate 350 issequentially exposed to the jet stream in order to make multiple cuts366. For example, the nozzles 82 may make one pass in the x directionand then step over in the y direction in order to make another pass inthe x direction. The linear cuts 366 generally extend from the edge ofthe first package 362 to the edge of the last package 368 in the group.In one embodiment, a serpentine path, which moves back and forth in thedirection of the x-axis while being incremented in the y-direction atthe end of each traverse, may be used. This embodiment will be describedin greater detail below.

After making the final linear cut, the gang manifold assembly 80 movesaway from the chuck 204 and the remnant 350′ of the substrate 350 isremoved from the chuck 204. This is generally accomplished manually orusing some sort of pick and place machine (not shown). After removingthe remnant 350′ the singulated packages 352 remain on the chuck 204.From here, the singulated packages can be further processed if desired.For example, they may be moved off of the chuck by a pick and placemachine or by sliding them via a transfer arm. Before doing so, however,the vacuum is turned off thereby releasing the suction force that hadbeen holding the singulated packages 352. A post package processingsystem that be used is described in greater detail in patent applicationSer. No. 10/227,163, titled “Integrated Circuit Processing System, filedon Aug. 22, 2002, which is herein incorporated by reference. A pick andplace machine that can be used is described in greater detail in patentapplication Ser. No. 10/226,630, titled “High Speed Pickhead”, filed onAug. 22, 2002, which is herein incorporated by reference.

FIGS. 23A and 23B are top view diagrams showing serpentine paths 380 and382, in accordance with one embodiment of the present invention. Theserpentine paths 380 and 382 may be used by the manifold assembly 80 tocut the packages from the substrate 350. FIG. 23A is directed at ydirection cuts, and FIG. 23B is directed at x direction cuts. In FIG.23A, the manifold assembly 80 is caused to move back and forth in thedirection of the y-axis while being incremented in the x-direction atthe end of each traverse. In so doing, the jet stream 384 is caused tomove across a predetermined area of the substrate 350 (along theserpentine path 380) thereby forming y—linear cuts 388 and x—linear cuts390. The predetermined area may correspond to a group of packages 352.

In FIG. 23B, the manifold assembly 80 is caused to move back and forthin the direction of the x-axis while being incremented in they-direction at the end of each traverse. In so doing, the jet stream 384is caused to move across a predetermined area of the substrate 350(along the serpentine path 382). The predetermined area may correspondto a group of packages 352. Paths 380 and 382 are generally positionedin the saw street 386 of the substrate 350, i.e., the area between eachof the packages 352 that is dedicated to dicing the substrate 350.

In one particular embodiment, the linear cuts 388 and 390 are performedat a first speed while the increments 392 and 394 orthogonal thereto areperformed at a second speed. The second speed is configured to be fasterthan the first speed in order to prevent cuts through the substrate andto decrease the cycle time associated with singulating the packages 352.The ratio between the second speed and the first speed may be betweenabout 40:1 to about 5:1, and more particularly about 20:1. By way ofexample, the linear cuts 388 and 390 may be cut at about 5 to about 10mm/s and the increments 392 and 394 may be cut at about 200 mm/s

FIG. 24 is a flow diagram of a cutting method 400, in accordance withone embodiment of the present invention. By way of example, the cuttingmethod may be associated with the diagram shown in FIGS. 23A and 23B.The cutting method 400 is typically performed with a z axis beam such asfor example a z axis jet stream as discussed throughout this document.The z axis beam is typically moved within a plane that is perpendicularto the z axis beam in order to implement a cutting sequence.Furthermore, the z axis beam is moved continuously without turning itoff.

The cutting method 400 generally begins at block 402 where the beam ismoved in a first direction at a first speed over a first distance. Byway of example, the first direction may be along the x or y axis. Thefirst speed is generally configured to allow the beam to cut through asubstrate so as to form a linear cut. The first distance generallycorresponds to the length needed to form the linear cut along the sideof one or more packages. In most cases, the linear cut is configured tospan more than one package, as for example, a row or column of packages.

Following block 402, the process flow proceeds to block 404 where thebeam is moved in a second direction at a second speed over a seconddistance. In most cases, the second direction is orthogonal to the firstdirection. By way of example, if the first direction is along the y axisthen the second direction is along the x axis (or vice versa). Thesecond speed is configured to be faster than the first speed. By way ofexample, it may be faster on an order of 5 to 40 times, and moreparticular about 20 times. The faster speed is used to prevent cuttingas well as to decrease the cycle time of the cutting sequence. Thesecond distance may be widely varied, however the second distance istypically smaller than the first distance in most cases.

FIG. 25 is a diagram of a singulation engine 500, in accordance with oneembodiment of the present invention. As shown, the singulation engine500 includes a gang manifold assembly 510 and a chuck assembly 512. Thegang manifold assembly 510 is shown in its initial or idle position.When a cut is to be made, the gang manifold 510 moves to a cuttingposition, which is generally over the chuck assembly 512. As shown, thegang manifold 510 includes a plurality of nozzles 514 that are coupledto a manifold 516. The manifold 516 is attached to a robot system 518configured to move the gang manifold assembly 510 between the initialand cutting positions and to move the gang manifold assembly 510 duringa cutting sequence. Although the robot system may vary, the robot systemin FIG. 25 corresponds to a SCARA robot system.

The chuck assembly 512, on the other hand, includes a first chuck 520and a second chuck 522. The first chuck 520 is configured to hold asubstrate during y axis cutting and the second chuck 522 is configuredto hold the substrate during x axis cutting. In this particularembodiment, the first and second chucks are positioned side by side. Thesingulation engine 500 also includes a holding tank (not shown)generally positioned below the two chucks 520 and 522. The holding tankis configured to store the slurry and receive the jet stream.

The singulation engine 500 also includes an abrasive slurry deliverysystem 530 that is operatively coupled to the holding tank via a recycleline 532 and to the nozzle manifold 510 via a discharge line 534. Therecycle line 532 is used to supply the slurry delivery system with usedslurry and the discharge line is used to delivery good slurry to thenozzle assembly. The used slurry may pass through a filtering system 536as for example the system shown in FIG. 10. Once filtered, the filteredslurry can be introduced into a slurry containment vessel 538. When theslurry containment vessel is filled with good slurry, a pump 540 may beused to force the good slurry out of the containment vessel 538 and intonozzle assembly 510 via the discharge line 534.

When the good slurry is forced out of the nozzles, a cutting sequencecommences. As should be appreciated, the robot system moves the nozzleassembly to the cutting position from the initial position before thegood slurry is forced into a cutting beam. During a cutting sequence,the nozzle assembly can be continuously repositioned via the variousarms of the robot system in order to follow the requisite cutting path.For example, the robot system may move the nozzle assembly in the ydirection when cutting over the first chuck 520 and in the x directionwhen cutting over the second chuck 522. If the spacing between nozzlesis large compared to the spacing between integrated circuit packages onthe substrate then multiple passes in both directions may be required inorder to fully singulate the substrate. The passes may overlap onanother.

In one embodiment, the angle of the nozzle assembly may be adjusted bythe robot system before performing a linear cutting sequence in order toreduce the spacing between cutting beams produced by the nozzles.Referring to FIGS. 26A and 26B, the nozzle adjustment will be describedin greater detail. As shown in FIG. 26A, the spacing D between thecutting beams does not coincide with the spacing d between devices orgroups of devices 550 on a substrate 552. The spacing D is typicallycontrolled by the position of the nozzles relative to one another. Inorder for the spacings d and D to match, the nozzles can move relativeto one another or the entire nozzle assembly can be rotated. Rotatingthe nozzle assembly is believed to provide the easiest solution. Asshown in FIG. 26B, the spacing D between the cutting beams can bereduced to match the spacing d between device 550 (d=D) by rotating theentire nozzle assembly θ while keeping the positions of the nozzlesrelative to one another fixed.

It should be noted that the configuration shown in FIG. 25 is not alimitation. For example, the first and second chucks may be positionedin line rather than side by side. Furthermore, more than one gangmanifold assembly may be used. For example, a first gang manifoldassembly may be used in conjunction with y axis cuts and a secondmanifold assembly may be used in conjunction with x axis cuts. Thisparticular configuration may require additional robot systems anddischarge lines.

FIG. 27 is a block diagram of a singulation engine 600, in accordancewith one embodiment of the present invention. The singulation engine 600is configured to produce one or more cutting beams 601, each of which iscapable of cutting through a substrate in order to form small discreteparts. The singulation engine 600 includes an abrasive delivery system602 and a nozzle system 604 operatively coupled to the abrasive deliverysystem 602. The abrasive delivery system 602 is configured to supply anabrasive slurry to the nozzle system 604, which includes one or morenozzles 605 configured to produce the cutting beams 601. By way ofexample, the abrasive delivery system 602 and nozzle system 604 maygenerally correspond to those shown in the previous figures.

As shown, the abrasive slurry delivery system 602 includes a slurryvessel 606, and one or more sources 608. The slurry vessel 606, whichserves as a central structure for receiving inputs from the sources 608,is configured to contain the abrasive slurry before its outputted to thenozzle system 604. The slurry vessel 606 is the location where theabrasive slurry is mixed before being delivered to the nozzle system604. As should be appreciated, each of the sources 608 is configured tosupply a different component to the slurry vessel in order to make upthe final concentration of the abrasive slurry before its outputted.

In the illustrated embodiment, the system 602 includes an abrasivesource 608A, a fluid source 608B, and a recycled slurry source 608C. Theabrasive source 608A is configured to introduce new abrasive materialinto the slurry vessel 606. The fluid source 608B is configured tointroduce a fluid such as water into the slurry vessel 606. The fluid ismixed with the abrasive to form the abrasive slurry. The recycled slurrysource 608C is configured to reintroduce previously used slurry backinto the slurry vessel 606. The recycled slurry may for example bereclaimed slurry that has been filtered.

All three sources 608 can be controlled to affect the abrasive to fluidconcentration of the abrasive slurry. For example, the amount ofabrasive, fluid and slurry introduced into the slurry vessel may beincreased or decreased to change the concentration of the outputtedabrasive slurry. The slurry concentration is typically controlled by acontroller 610. The controller 610 may be the controller of the entiresingulation engine 600 or it may be a dedicated controller of theabrasive slurry system 602. In either case, the controller 610 isconfigured to execute instructions and carry out operations associatedwith the abrasive slurry system 602. For example, using instructionsretrieved from memory, the controller 610 may control the reception andmanipulation of input and output data between the various components ofthe abrasive slurry system 602. As shown, the controller 610 isoperatively coupled to each of the sources 608 so that their output canbe adjusted. That is, the controller 610 sends a control signal to thesources 608 so as to affect the amount of abrasive, fluid and recycledslurry in the slurry vessel 606.

In order to properly control the slurry concentration, the abrasiveslurry system 602 generally includes one or more concentration sensingdevices 612. The concentration sensing devices 612 are configured toperform measurements so that the concentration (particle count) of theabrasive, fluid and/or slurry can be ascertained. The concentrationssensing devices 612 are also configured to report this information tothe controller 610. When reported, the controller 610 interprets themeasurement data in accordance with its programming. By way of example,the controller 610 may calculate the concentration based on themeasurement data, and thereafter determine if a change at one of theinputs is needed in order to produce the desired concentration output.

The concentration sensing devices 612 may be placed at various points inthe abrasive slurry system 602 to provide concentration feedback to thecontroller 610. The concentration sensing devices 612 may for example beplaced at any of the inputs or outputs of the slurry vessel 606. Whenplaced at the inputs, the controller 610 monitors the concentration ofthe abrasive source 608A, fluid source 608B and/or slurry source 608C.When placed at the outputs, the controller 610 monitors theconcentration of the outputted slurry, i.e., the slurry that is sent tothe nozzles 605 in order to perform a cutting operation.

In one implementation, the controller 610 compares the measuredconcentration to a desired concentration, and if different, refers to atable or algorithm that informs the controller 610 as to what changesneed to be made at each of the sources 608 in order to produce thedesired concentration. If a change is needed, the controller 610 sends acontrol signal indicating the change to the appropriate source(s) 608.The sources 608 are configured to receive the control signal from thecontroller 610, and to adjust the output thereof in order to affect theabrasive slurry concentration. By way of example, in order to increasethe abrasive to fluid ratio in the slurry, a first control signal maycause the abrasive source 608A to output more abrasive and/or a secondcontrol signal may cause the fluid source 608B to reduce the output offluid. Along a similar vein, in order to decrease the abrasive to fluidratio of the slurry, a first control signal may cause the abrasivesource 608A to output less abrasive and/or a second control signal maycause the fluid source 608B to increase the output of fluid. In mostcases, the sources 608 are controlled as part of a continuous feedbackloop in order to maintain the desired abrasive slurry concentrationduring a particular cutting operation. By way of example, the abrasivemay make up between 5% to about 40% of the total slurry. In oneparticular example, slurry contains about 10 parts abrasive and 90 partsfluid.

In one embodiment, the abrasive source 608A is configured with multipleabrasive containers 614 configured to hold the abrasive material. Anynumber of containers 614 may be used. By utilizing multiple containers614, downtime associated with loading new abrasive material can bereduced. For example, when one container is emptied, the control systemcan switch to a full container. Once switched, the emptied container canbe refilled. This process can be performed continuously therebyeliminating downtime due to loading new material. In cases where thecontainers 614 are emptied at the same time, the control system canswitch to the recycled slurry source 608C until the new material isadded into the system 602. The containers 614 may be fixed or they maybe removable from the delivery system 602. If removable, the emptiedcontainer can be removed, and a full container can be inserted in itsplace.

FIG. 28 is a diagram of a concentration sensing device 620, inaccordance with one embodiment of the present invention. Theconcentration sensing device 620 may generally correspond to the sensingdevice shown in FIG. 27. The concentration sensing device 620 generallyincludes a sensor 622 and a sensing circuit 624. The sensor 622 producessignals associated with the concentration and the sensing circuit 624acquires the signals from the sensors 622 and supplies the acquiredsignals to a host controller. The sensor 622 may be based on a widevariety of technologies including but not limited to optical orultrasonic technologies. Optical sensors may for example includeturbidity sensors. With regards to the sensing circuit 624, the sensingcircuit 624 may send the raw data to the host controller and/or thesensing circuit 624 may be configured to process the raw data beforesending it to the host controller. For example, the sensing circuit 624may read the pulses from the sensors 622 and turn them into data thatthe host controller can understand.

To elaborate, the sensor 622 generally includes one or more emitters 626and one or more detectors 628. The emitters 626 are configured to applya signal 629 transverse to the moving slurry 630 (or component of theslurry) and the detectors 628 are configured to detect changes in thesignal 629 that are attributable to the slurry concentration. In opticalsensors, the emitters 626 are light emitting devices that direct lightor radiation at the slurry 630, and the detectors 628 are lightdetectors that detect changes in the light or radiation afterintersecting the moving slurry 630. The light emitting devices maygenerally correspond to light emitting diodes and the light detectorsmay generally correspond to photocells, photodiodes, and the like. Inultrasonic sensors, the emitter 626 is a wave generator that directssonic waves at the slurry 630, and the detectors 628 are sonic wavedetectors that detect changes in the sonic waves after they intersectthe slurry 630.

Like the sensor 622, the sensing circuit 624 may be widely varied. Thesensing circuit 624 is generally configured to acquire the measurementsignals from the detectors 628 and report the measurement data to a hostcontroller. The sensing circuit 624 may include an analog to digitalconverter (ADC) 632 configured to digitize the incoming analog signals.That is, the ADC converts the analog signals produced at the detectors628 into an outgoing digital signal 634 that can be easily received bythe host controller. The input to the ADC 632 generally corresponds to avoltage having a theoretically infinite number of values. The voltagevaries according to the intensity of the measurements (e.g., lightintensity, wave intensity). The output to the ADC, on the other hand,has a defined number of states. The states generally have predictableexact voltages and currents, which can be easily read by the hostcontroller.

FIGS. 29 and 30 are diagrams of an optical concentration sensor 640, inaccordance with one embodiment of the present invention. The opticalconcentration sensor 640 may generally correspond to the sensor shown inFIG. 28. The optical concentration sensor 640 includes a housing 642that defines a slurry passage 644 therein. The slurry passage 644 isconfigured to distribute a moving abrasive slurry 645 between an inletcoupling 646 and an outlet coupling 648. The inlet coupling 646 may forexample be fluidly coupled to a slurry vessel through a first hose andthe outlet coupling 648 may be fluidly coupled to a nozzle assemblythrough a second hose. The inlet and outlet coupling may be coupled tothe hoses via c clamps, hose clamps, quick disconnect couplings, and thelike. The housing 642 and more particularly the inner surface 643 of thehousing 642 is formed from a material that is resistant to a movingabrasive slurry 645. By way of example, the inner surface 643 may beformed from ceramics, carbide, stainless steel (e.g., 316 stainlesssteel) and/or the like.

The optical concentration sensor 640 also includes a light source 650and one or more light detectors 652. The light source 650 is configuredto direct light 654A into the passage 644, and the light detectors 652are configured to detect light 654B traveling out of the passage 644.When the slurry 645 is present inside the passage 644, the light 654A isdirected into the slurry 645 and the light detectors 652 detect thelight 654B that emanates out of the slurry 645. The light 654B emanatingout of the slurry 645 can be transmitted and/or scattered light.Transmitted light is that light, which passes through the slurry 645without intersecting any particles 656 contained therein. Scatteredlight is that light which intersects particles 656 and thereforescatters in all directions. The intensity of the transmitted light andscattered light 654B is directly related to the concentration of theslurry 645. For example, when the ratio of abrasive to fluid is high,more light will be scattered and less light will be transmitted becauseof the greater number of particles in the slurry, and when the ratio ofabrasive to fluid is low, more light will be transmitted and less lightwill be scattered because of the reduced amount of particles in theslurry. In one embodiment, only the transmitted light is detected. In aanother embodiment, only the scattered light is detected. In yet anotherembodiment, both the transmitted light and the scattered light aredetected. By detecting both, a more accurate concentration reading maybe obtained.

In order to allow the light 654 to be directed into and out of thepassage without comprising the slurry 645, the housing generallyincludes a window 658 formed from a light passing material(s). Thewindow 658 may for example be formed from translucent or semitranslucent materials. The window 658 generally covers an opening 660 inthe housing 642 and in some cases is positioned inside the opening 660in the housing 642 (as shown). The window 658 may be one continuouspiece (as shown) or it may be several pieces that are only positioned infront of the light source 650 and detectors 652. When separate pieces,the spaces found between the windows may be a portion of the housing orsome other filling structure. Furthermore, the inner surface of thewindow 659 may protrude, be recessed or flush with the inner surface 643inside the passage 644. In most cases, the inner surface 659 of thewindow 658 is made flush with the inner surface 643 of the housing 642so as to provide a continuous surface thereby allowing a more uniformflow of slurry 645 through the sensor 640. Moreover, the inner surface659 of the window 658 is formed from a material that can substantiallywithstand a slurry environment and does not substantially contribute tocontamination. As should be appreciated, even though the slurry 645typically flows laminarly through the sensor 640, the abrasive particles656 at the periphery of the passage 644 may scratch the window 658 asthey travel through the sensor 640. By way of example, the window 658may be formed from quartz, or glass that is coated with a scratchresistant layer.

The configuration of the sensor 640 may be widely varied. Although thisis not a requirement, the housing 642 as well as the passage 644 isconfigured to be substantially cylindrical in shape with substantiallystraight walls. The light source 650 and detectors 652 and window 658may be placed anywhere along a longitudinal axis 662 of the housing 642.In most cases, the light source 650 and detectors 652 are positioned inthe same plane and are disposed at various positions about the peripheryof the window 658. As shown in FIG. 30, the light source 650 anddetectors 652 are disposed radially about a longitudinal axis 662 of thehousing 642 with each of these components being axially oriented suchthat their working centerlines point toward the longitudinal axis 662(e.g., perpendicular). The light source 650 and detectors 652 can beseparated by various angles. By way of example, they may be separated by90 degree increments about the periphery of the housing 642. It shouldbe understood however that the angles may vary according to the specificdesign of sensor 640. In addition, the light source 650 and detectors652 are typically disposed outside of the housing walls. It should benoted however that these components may also be disposed within thehousing walls as for example when the window 658 only partially fillsthe opening 660 in the housing 642. Alternatively, these components maybe embedded inside the window 658.

In the illustrated embodiment, and referring to FIG. 30, the opticalconcentration sensor includes a single light source 650 and a pluralityof light detectors 652. The single light source 650 shines light 665 atthe slurry 645 through the window 658. Light that passes straightthrough the slurry 645, i.e., transmitted light 667, is collected by afirst detector 652A and the light that reflects off the particles, i.e.,scattered light 669, is collected by a second detector 652B. The firstlight detector 652A is placed directly across from the light source 650,and the second light detector 652B is angled such that the centerlinetraverses the centerline of the light source 650. By way of example, thefirst detector 652A may be placed at 180 degrees and the second detector652B may be placed at 90 and/or 270 degrees relative to the light source650. The light source 650 may for example be an infrared light emittingdiode (LED), and the light detectors 652 may be photocells orphotodiodes. The detectors 652 generally produce voltages that vary inaccordance with the light intensity. The first light detector producesvoltages in accordance with the light intensity of the transmittedlight, and the second light detector produces voltages that vary inaccordance with the intensity of the scattered light. The voltages forboth detectors 652 are monitored and subsequently translated intoconcentration at a host controller or alternatively at a sensingcircuit.

FIG. 31 is a slurry control method 680, in accordance with oneembodiment of the present invention. The method 680 may generally beperformed using the system shown in FIG. 27. The method begins at block682 where measurements are performed on the moving slurry. Themeasurements may for example be light intensity measurements produced byone or more light detectors. Following block 682, the process flowproceeds to block 684 where the measurements are translated intoconcentration. This may be accomplished with an algorithm or table thatrelates measurements with concentration. Following block 684, theprocess flow proceeds to block 686 where the measured concentration iscompared with the desired concentration. The desired concentration maybe a concentration that was previously determined to produce the desiredcut. By way of example, the desired concentration may be foundexperimentally. Following block 686 the process flow proceeds to block688 where the inputs are controlled based on the comparison. The inputsmay for example be abrasive, fluids or already mixed slurry. By way ofexample, if the measured concentration is lower than the desiredconcentration, then more abrasive and/or less fluid may be delivered,and if the measured concentration is higher than the desiredconcentration, then less abrasive and/or more fluid may be delivered.

FIG. 32 is a concentration determination method 700, in accordance withone embodiment of the present invention. The method may for examplecorrespond to block 684 in FIG. 31. The method begins at block 702 wheremeasurement data is obtained. The measurement data may for example belight intensity measurements generated from an optical sensing device.The measurement data varies according to the amount of particles in theslurry and thus the measurement data carries information concerning theconcentration of the slurry. Following block 702, the process flowproceeds to block 704 where the actual concentration of the slurry iscalculated. The calculation generally includes receiving measurementdata 702, control setting data 705A and calibration data 705B.

The control setting data 705A may be preprogrammed data or measureddata. The control setting data 705A typically includes abrasive size andtype, flow rate of the slurry, concentration and the like. Thecalibration data 705B, on the other hand, generally includes arelationship relating measurement data and control setting data withconcentration data. The calibration data may be determined usingexperimentation or simulation. The calibration data may take many formsincluding but not limited to tables, graphs, curves, equations, and thelike. Using the calibrated relationship, the measurement data, which mayinclude values from multiple detectors, and control setting data, whichprovides data about the current slurry, can be used to calculate theconcentration for the moving slurry. For example, the currentmeasurement and control setting data may be compared to a list ofbaseline measurement and control setting data that has been calibratedto concentration. When a match is found the calibrated concentrationcorresponds to the measured concentration. Following block 704, theprocess flow proceeds to block 706 where the measured concentration isoutputted. The measured concentration may for example indicate theabrasive to fluid ratio of the slurry.

FIG. 33 is a simplified illustration of an abrasive distributionsequence 720, in accordance with one embodiment of the presentinvention. The abrasive distribution sequence 720 is designed toseparate the typically dirty filling process from clean rooms wheresingulation processes typically take place. Abrasive is typicallydelivered to clean rooms in sacks and the sacks are loaded into aholding tank before being delivered to a slurry vessel. This is aninherently dirty process since the bags are cut open and the abrasive ispoured into the holding tank. During either of these steps, abrasive mayspill or leak into undesirable areas thus contaminating the clean room.Furthermore, the sacks are typically heavy and awkward to handle.

The abrasive distribution sequence 720 generally begins at step A wherethe raw materials are received at the filling room 722 that is separatefrom the clean room 724. The filling room 722 is a dedicated area whereabrasive is prepackaged. The filling room 722 may be onsite or offsiterelative to the clean room 724. The raw materials typically include bagsof abrasive 726 and empty abrasive containers 728. The containers 728are formed from a somewhat rigid material unlike the sacks (e.g., paper)and thus they are easier to handle. The containers may for example beformed from metals, plastics and the like. Once received, the abrasive730 can be loaded into a hopper 732 or similar filling system andthereafter the containers 728 can be filled with abrasive 730 as shownin step B. Once filled, each of the containers 728 is sealed with a cap733 and cleaned as shown in step C. In most cases, the filled containers734 are packaged in a group 735 and sent together to the clean room 724as shown in step D.

Following step D, an operator selects one of the filled containers 734for loading into a singulation engine as shown in step E. The filledcontainers 734 are typically sized and dimensioned for easy handling.The filled containers may for example weigh about 50 lbs and they mayinclude a handle 736. Following step E, the sequence 720 proceeds tostep F where the container 734 is loaded into an abrasive slurrydelivery system. The abrasive slurry delivery system may for examplecorrespond to any of those shown previously. Because of the modulardesign, the abrasive slurry delivery system includes a receptacle 740for receiving the filled container 734. The receptacle 740 and filledcontainer 734 cooperate to form the abrasive source. The cap 733 isremoved and the top of the container 734 is inserted and lockably sealedto the receptacle 740. This may be accomplished with threads, clamps,quick release couplings, etc. The receptacle 740 generally includes afluid inlet 742 and a wet abrasive outlet 744. Once sealed, the fluidinlet 742 introduces a fluid such as water into the container 734 asshown in step G. As should be appreciated, the abrasive 730 is easier totransfer when wet. The fluid mixes and agitates the abrasive 730 and apressure system forces the wet abrasive into the wet abrasive outlet 744where the wet abrasive is delivered to a slurry vessel. In some cases,the abrasive slurry delivery system may include a vibrator 746 forkeeping particles from adhering to the sides of the container 734.

During slurry delivery, the wet abrasive is continuously drawn out ofthe container 734 until it is empty (or near empty) as shown in step H.Sensors may be used to monitor the amount of abrasive in the container734. The sensors may be similar to those described previously. Thesensors may also be in the form of a load cell that continuouslymeasures the weight of the container 734. Through these measurements,the amount of abrasive in the container 734 can be ascertained. Onceemptied, the process flow proceeds to step I where the emptied container750 is removed from the receptacle 740 and a new filled container 734 isinserted onto the receptacle 740 (step F). The emptied container 750 iscapped and removed from the clean room 724. Once removed from the cleanroom 724, the empty container 750 can be trashed, recycled or reused. Ifreused, the container 750 is cleaned and returned to the filling room722 where the process starts over.

FIG. 34 is diagram of an abrasive source 760, in accordance with oneembodiment of the present invention. The source 760 includes at least anabrasive canister 762 and an abrasive delivery receptacle 764. Thecanister 762, which comes preloaded with abrasive material, is a modularunit that can be installed and removed to and from an abrasive slurrydelivery system with simplicity and ease. The receptacle 764, on theother hand, resides within the delivery system and provides a means foroperatively coupling the canister 762 to the delivery system. By way ofexample, the abrasive canister 762 and receptacle 764 may generallycorrespond to the container and receptacle shown in FIG. 33.

To elaborate, the canister 762 includes a neck 766 and a body 768. Thebody 768 provides a structure for holding and carrying the abrasivematerial. The body 768 is preferably configured to contain enoughabrasive for one or more hours of operation while still allowing it tobe easily manipulated by an operator in its full state. The body 768 maycontain between about 25 to 100 pounds, more particularly between about50 and about 75 pounds, and even more particularly about 50 pounds. Theneck 766, on the other hand, provides a structure for filling andremoving the abrasive material. The neck 766, which includes an opening770 leading to a chamber 772 defined by the body 768, is configured toreceive a cap 774 thereon for closing off and sealing the chamber 772.The cap 774 may be threaded or snapped on the neck 766. The neck 766 isalso configured to engage the receptacle 764 so that the abrasivematerial can be introduced into the delivery system.

The receptacle 764 includes a base 776 and a pair of tubes 778. The base776 may be free floating or it may be structurally attached inside anabrasive loading area of the delivery system. The base 776 is configuredto temporarily receive the neck 766 of the canister 762. The base 776may receive the neck 766 upside down (as shown), and in other cases theneck 766 may be positioned right side up or sideways when engaging thebase 776. More particularly, the neck 766 and the base 776 areconfigured for mating engagement so as to provide both a mechanical anda fluid connection between the canister 762 and the receptacle 764.These elements have similar cross sectional shapes and sizes so they fitwithin one another. In most cases, the neck 766 is secured and sealed tothe base 776 in order to prevent the leakage of abrasive material andfluids. This may be accomplished with seals such as o-rings, washersand/or gaskets and fasteners such as bolts and screws. By way ofexample, a washer may be placed at the interface between the neck 766and the base 776 and bolts may be placed through several mounting holeslocated on mating flange portions of the neck 766 and base 776. Whenbolted together, the washer is sandwiched between the neck 766 and thebase 776 thus sealing the interface therebetween.

While fasteners such as bolts and screws work well, it is oftennecessary to unfasten and remove each of these fasteners in order tomount or remove the neck from the base. Unfortunately, this is timeconsuming and cumbersome process. Furthermore, it requires tools andmore than one hand. In accordance with one embodiment, therefore, theconnection between the neck 766 and the base 776 is arranged forinsertion and removal with minimal effort and without tools. This may beaccomplished with quick release couplings that enable a user to easilyand quickly secure and release the head to and from the base. The quickrelease couplings may take many forms including but not limited tolatches, clamps, threads, detents, flexures, snaps and the like. By wayof example, the inner periphery of the base 776 may include an internalthread that mates with an external thread on the outer periphery of theneck 766 (or vice versa). In this arrangement, the neck 766 is securedand sealed to the base 776 by screwing the neck 766 onto the base 776.The external thread on the neck 766 may also receive a threaded cap 774.

Moving along, when the neck 766 is mated with the base 776, the tubes778 extend into the chamber 772 of the body 768. A first tube 778A isconfigured to carry a fluid such as water into the chamber 772, and asecond tube 778B is configured to carry the wetted abrasive material outof the chamber 772. The first tube 778A is fluidly coupled to a fluidsource 780 that delivers the fluid at low pressures as for examplearound 60 psi via a fluid line 782. The second tube 778B is fluidlycoupled to a slurry vessel 784 via a slurry line 786. In order to movethe wet abrasive through the slurry line 786, the wet abrasive materialis typically pressurized as for example using a pump 788. In some cases,the tubes 778 include tapered sections 790 at their ends in order tomake insertion into the abrasive material easier, i.e., the taperedsections 790 cut through the abrasive material contained within thechamber 772 better than a blunt end.

The base 776 and tubes 778 may be formed from a wide variety ofmaterials, but generally from materials that are resistant to abrasivematerials. By way of example, the base 776 and tubes 778 may be formedfrom stainless steel or plastic. Furthermore, the tubes 778 may beintegrally connected to the base 776 or they may be separate components.When separate, the interface therebetween may need a rubberized seal 792in order to prevent leaks.

Moreover, in order to facilitate the mounting and removal of thecanister 762 to and from the receptacle 764, the canister 762 generallyincludes one or more handles 794 that allow a user to easily manipulateand move the canister 762. The handles 794 may be separate or integrallyformed with the canister 762. When separate, the handle 794 may beattached using fasteners, clamps, straps and the like. When integral (asshown), the body 768 and handle 794 form a single continuous piece. Byway of example, the handle 794 and body 768 may be formed from a singlepiece of material, or the handle 794 may be welded or glued to thesurface of the body 768. The handle 794 may be connected to any portionof the body 768 including the top, sides and/or bottom surfaces. Theposition of the handle 784 generally depends on how the canister 762 isconnected to the receptacle 764.

In the illustrated embodiment, the handle 794 is placed on the top ofthe body 768 and the canister 762 is loaded into the receptacle neck 766down. Although not shown, a membrane may be attached over the opening770 in the neck 766 in order to keep the abrasive form pouring out ofthe neck 766 when positioned neck down. The tapered ends of the tubes778 pierce through the membrane during placement. In most cases, themembrane is configured to seal the interface between the membrane andthe piercing tubes 778 in order to prevent particles from leaking out.By way of example, the membrane may be formed from a flexible film orfoil that conforms to the shape of the tubes 778.

Moreover, the neck 766 is coupled to the base 776 via a quick releasecoupling. The quick release coupling includes a base side mating featureand a neck side mating feature that are cooperatively positioned so thatthey engage when the neck 766 is inserted into the base 776. Althoughthe mating features may be widely varied, in this particular arrangementthe neck 766 (or body) includes a guide 796 and the base 776 (or someother structure) includes a pin 798 that is positionable relative to theguide 796. The guide 796 may be a protrusion that extends outside theperiphery of the neck 766 or it may be a recess that extend into theneck 766. In either case, the guide 796 is configured to engage the pin798 upon insertion of the neck 766 into the base 776 and to capture thepin 798 when the canister 762 is rotated relative to the receptacle 764.Once captured, the neck 766 is secured to the base 776. The canister 762may be rotated by twisting the canister 762 via the handle 794 locatedon the top of the body 768.

In order to seal the interface between the neck 766 and the base 776,the guide 796 may be configured in such a way as to force the neck 766against the base 776 when the canister 762 is further rotated via thehandle 794. As shown in FIG. 34B, the guide 796 may include a taperedsection 800 that moves against the stationary pin 798 during rotation ofthe canister 762. As the tapered section 800 moves against the pin 798,the canister 762 is forced downwards. In essence, the pin 798 urges theneck 766 into sealed engagement with the base 776. In most cases, thelength of the guide 796 is configured to place the neck 766 into sealedengagement upon a slight turn of the canister 762 relative to thestationary base 776. By way of example, about a 1/32 to about a ½ turn,and more particularly a ¼ turn may be used. One advantage of thisarrangement is that the user does not have to use tools or manipulate alocking feature such as a latch.

To elaborate, the guide 796 generally includes an entry point 802 and afinal point 804. The entry point 802 represents the area of the guide796 that initially receives the pin 798. The entry point 802 may beflared downwards in order to facilitate the easy placement of the pin798 relative to the guide 796. The final point 804 represents the areaof the guide 796 that prevents further rotation and that snaps the neck766 into locked relationship with the base 776. The final point 804 maybe flared upwards in order to facilitate the snapping action that locksthe neck 766 to the base 776.

During insertion, the pin 798 is placed at the entry point 802 thathelps guide the pin 798 into and out of engagement with the guide 796.When the operator first rotates the canister 762, as for example via thehandle 794, the guide 796 captures the pin 798. This action also causesthe pin 798 to move against the guide 796. Upon further rotation of thecanister 762, the tapered section 800 of the guide 796 presses againstthe pin 798 thereby forcing the canister 762 downwards towards thereceptacle 764. When the canister 762 is finally rotated, the pin 798 islocated at the final point 804 where the downward force is increasedbecause of the increased slope. As a result, the neck 766 is sealedagainst the base 776.

Because the tubes may produce a torque on the membrane when the canisteris rotated, the membrane may include a moveable portion that can rotaterelative to the canister along with the tubes when the canister isrotated. Alternatively, the quick release coupling may be designed insuch a way as to secure the neck to the base via a linear motion ratherthan a rotation thereby eliminating the torque on the membrane. in thisembodiment, the canister is placed straight onto the receptacle. Alsoalternatively, the tubes may be positioned in a manner that reducestorque as for example next to one another. It should also be noted thatthe membrane may be made from a flexible material so that it canwithstand some of the rotation. In addition, the rotation may beminmized so that the torque is small.

FIG. 35 is an exploded perspective view of an abrasive canister 810, inaccordance with one embodiment of the present invention. By way ofexample, the abrasive canister 810 may generally correspond to theabrasive canister shown in FIG. 34. The abrasive canister 810, which ispreloaded with abrasive material 812, is a modular unit that can beinstalled and loaded into a slurry delivery system with simplicity andease. The abrasive canister 810 includes a neck 814 and a body 816formed from a single continuous piece of plastic material. The neck andbody 814 and 816 may be formed using conventional plastic formingprocesses such as injection molding.

The body 816 is configured for holding the abrasive material 812. Thevolume defined by the body 816 may for example be configured to holdabout 50 pounds of abrasive material. The body 816 includes a carryingand twisting handle 818 at its top end. The handle 818 is generallydimensioned for receiving a hand, and for providing structural supportduring twisting motions, as for example when the canister 810 isconnected to a receptacle. The body 816 may also include one or morequick lock guides 820 in order to secure and seal the neck 814 relativeto a base of a receptacle. In this embodiment, the guides 820 protrudeout of the outer surface of the body 816, and are configured to receivea pin on its upper surface. The pin may be attached to the receptacle orsome other structure attached to the receptacle. The body 816 may beformed from a clear material or it may include a clear window 822 forvisibility in order to determine when the abrasive material 812 is low,i.e., an operator can visual see when the abrasive is low or an opticalsensor can be used. By way of example, the optical sensor may transmitand receive light through the clear material or clear window.

The neck 814, which is positioned at the bottom end of the body 816, isconfigured to receive a cap 828, which acts as a cover for filledcanisters when not in use. The cap 828 and the head 814 may includethreads 830 so that the cap 828 can be screwed onto the neck 814. Theneck 814 is also configured for insertion into a receptacle. Whensecured together, the abrasive material 812 stored in the canister 810can be introduced into a slurry vessel. When removed, the canister 810is free from the delivery system such that it can be refilled, replaced,recycled, destroyed, etc.

In order to further seal the opening in the neck 814, the canister 810may include a membrane 832 that attaches to the top edge of the neck814. The membrane 832 adds additionally protection against contaminationand leakage. During use, the membrane 832 may be removable (peeled off),or it may be permanently attached (left on). When peeled off, the tubesof the receptacle can be directly introduced through the neck 814. Whenleft on, the tapered ends of the tubes penetrate the membrane 832 thusleaving the canister 810 substantially sealed during use. This alsoallows the canister 810 to be positioned in the receptacle in thedownward facing position, i.e., prevents the abrasive material 812 frompouring out. By way of example, the membrane 832, which is typically athin film or foil may be formed from various materials including but notlimited to paper, rubber, plastic, and/or the like. Furthermore, themembrane 832 may be attached with an adhesive such as glue. The adhesiveis generally applied to the upper edge of the neck 814. The amount andtype of adhesive generally determines whether or not the membrane 832can be peeled off.

The advantages of the invention are numerous. Different embodiments orimplementations may have one or more of the following advantages. Thepresent invention provides a cost-effective cutting process for finegeometry devices with both straight line and curvilinear edges. Inaddition, the water jet cutting process is material non-specific;therefore, laminates and coated devices with both ductile a brittlematerial can be cut in a single pass. Furthermore, the cutting beaminteracts with a substrate only along the vertical axis therebypreventing the formation of shear forces. The devices are thereforeretained in their intended position and cut geometries remainconsistent. Another benefit of this water and slurry-based method is thecontinual renewal of inexpensive abrasive (Al₂O₃ or garnet). Theabrasive is never “dulled” by ductile or compliant materials. Theprocess remains inexpensive and robust, even when singulating laminatesof very dissimilar materials. Finally, a single nozzle acts as a pointsource for cutting, thus, enabling curvilinear cut paths as for examplephotonic devices.

A comparison between a conventional blade saw and a jet stream is shownbelow in Table 1. The data in Table 1 was obtained using a firstgeneration lab model. The jet stream was produced using a modifiedJetsis microjet system.

TABLE 1 Jet Stream Blade Saw BGA Minimum Device Size 0.5 mm × 0.5 mm 4.0mm × 4.0 mm 8 × 8 FBGA Throughput 160 mm/sec* 100 mm/sec 144 units/stripChipping <10 μm <40 μm Consumable Cost 0.001119 USD/unit 0.022222USD/unit 0.000017 USD/pin 0.000347 USD/pin QFN Minimum Device Size 0.5mm × 0.5 mm 4.0 mm × 4.0 mm 4 × 4 QFN 176 Throughput 160 mm/sec* 18mm/sec units/strip Chipping <10 μm <40 μm full copper no etchBurrs/Smearing <10 μm <50 μm Consumable Cost 0.000852 USD/unit 0.104748USD/unit 0.000053 USD/unit 0.0065467 USD/pin Photonic Curvilinear CutYes No 8″ Si Wafer Throughput 160 mm/sec* Not Measurable Chipping <10 μm<50 μm Consumable Cost Low Acceptable *the throughput was limited byprototype table speed

While this invention has been described in terms of several preferredembodiments, there are alterations, permutations, and equivalents, whichfall within the scope of this invention. It should also be noted thatthere are many alternative ways of implementing the methods andapparatuses of the present invention. For example, although theinvention has been described in terms of processing integrated circuits(in all its various forms), it should be noted that the invention may beused to process any device. For example, the invention may be used toprocess semiconductor wafers. In addition, the invention may be used toprocess discrete electrical components such as resistors, transistors,capacitors and the like. The invention may also be used to processbiotechnological devices, optical devices, opto-electrical devices,electromechanical devices (e.g., MEMS-micro electromechanical) or thelike. It is therefore intended that the following appended claims beinterpreted as including all such alterations, permutations, andequivalents as fall within the true spirit and scope of the presentinvention.

1. A singulation engine for performing cutting operations onsemiconductor substrates, comprising: a slurry vessel for mixing anabrasive slurry before the abrasive slurry is delivered to a nozzlesystem; an abrasive source configured to introduce new abrasive into theslurry vessel a fluid source configured to introduce new fluid into theslurry vessel; a recycled slurry source configured to reintroducepreviously used abrasive slurry back into the slurry vessel; one or moreconcentration sensing devices configured to perform measurements so thatthe abrasive slurry concentration can be ascertained; a controllerconfigured to control the amount of abrasive, fluid and recycledabrasive slurry introduced into the slurry vessel based on theconcentration measurements.
 2. The singulation engine as recited inclaim 1 wherein the concentration sensing device comprises: a sensorthat produces signals associated with the slurry concentration; and asensing circuit that acquires the signals from the sensors and suppliesa concentration signal to the controller.
 3. The singulation engine asrecited in claim 2 wherein the sensor is an optical sensor or anultrasonic sensor.
 4. The singulation engine as recited in claim 2wherein the sensor includes one or more emitters configured to apply asignal transverse to a moving abrasive slurry and one or more detectorsconfigured to detect changes in the signal that are attributable to theslurry concentration.
 5. The singulation engine as recited in claim 4wherein the sensor includes one or more light emitting devices thatdirect light or radiation at the moving abrasive slurry, and one or morelight detectors that detect changes in the light or radiation afterintersecting the moving abrasive slurry.
 6. The singulation engine asrecited in claim 2 wherein the sensing circuit includes an analog todigital converter configured to convert analog signals produced at thesensors into outgoing digital signals for reception at the controller.7. The singulation engine as recited in claim 1 wherein a concentrationsensing device is located at the output of the slurry vessel.
 8. Thesingulation engine as recited in claim 7 wherein the controller comparesmeasured concentration of the outputted abrasive slurry to a desiredconcentration of the outputted abrasive slurry and changes the output ofat least one of the sources if the two are different in order to producethe desired concentration of the outputted abrasive slurry.
 9. Thesingulation engine as recited in claim 8 wherein the sources arecontrolled as part of a continuous feedback loop in order to maintainthe desired concentration of the abrasive slurry during a particularcutting operation.
 10. The singulation engine as recited in claim 1wherein the abrasive source includes multiple containers configured tohold abrasive.